photo of milk bar birthday cake on white plate against white brick backdrop

About The Milk Bar Birthday Cake

This Milk Bar Birthday Cake recipe is a homemade version of the most popular cake from famed New York City bakery, Milk Bar!

The birthday cake is made with layers of white cake studded with rainbow sprinkles, cream cheese frosting, and a crunchy streusel made from birthday cake crumbs.

Although I write that the recipe makes a 6-inch, 3-layer cake, it actually has MANY more layers. Why? The recipe instructs you to layer the first layer of the cake with a vanilla milk soak, then birthday cake crumbs, and frosting before starting with another layer of cake. All in all, it equates to about 11 different layers of cake, soak, crumbs, and frosting! 

I’ve made lots of funfetti recipes (like Rainbow Unicorn Cake or Small Batch Funfetti Cake), but this birthday cake recipe is one of my favorites. The recipe comes from Christina Tosi, the famed pastry chef behind Milk Bar bakery and her first cookbook, Momofuku Milk Bar. For even more fun and creative cake recipes, check out Hummingbird High’s full list of cake recipes!

@hummingbirdhigh feeling nostalgic and grateful on my 35th #birthday #over30 #bakingrecipe #bakingtiktok ♬ Married Life (From “Up”) – Sergy el Som

What is Momofuku Milk Bar?

Momofuku Milk Bar first exploded into the bakery scene in the mid-2010s as a companion bakery to famed restaurant Momofuku in New York City. It quickly became popular thanks to unique desserts like cereal milk-flavored soft serve and multi-layered naked cakes like this birthday cake.

These days, the bakery simply goes by the name “Milk Bar” and has several locations in other cities beyond New York. You can even buy some of their baked goods at Target and Whole Foods! I also don’t think Christina Tosi works in the kitchens anymore—instead, she appears on TV as a judge on several cooking shows like MasterChef.

Why is the cake naked?

According to Christina, she and her team worked hard to pack the layer cakes at the bakery with different flavors, textures, and more. They wanted their hard work (and all the layers!) to be visible instead of hidden underneath frosting! I love it.

Prior to their cakes, naked-style cakes weren’t really much of a thing. I believe Milk Bar pioneered the naked cake trend!

photo of milk bar birthday cake close up with lots of birthday cake crumbs

Why You Should Make The Recipe

Here are all the reasons to make the Milk Bar Birthday Cake recipe:

This recipe makes a homemade version of a famous bakery dessert: Milk Bar birthday cake.

I personally love tasting famous bakery desserts and taking on the challenge of recreating them at home. Luckily, many of my favorite bakeries sell cookbooks that enable me to do so! Like Milk Bar—this recipe comes from their self-titled cookbook. I love knowing that I can bake a cake (that typically sells for $50!) in my own kitchen.

And indeed—this Milk Bar birthday cake goes above and beyond a traditional layer cake recipe. From its unique combination of flavors to all the different textures in the cake, it really does taste like a pro made it! Amazing.

This is a great recipe for folks looking to level up their cake baking skills.

Because this recipe comes from a professional bakery, it introduced me to many new baking ingredients and techniques I wouldn’t have picked up on my own. To wit—most cake recipes instruct you to make the layers in individual round cake pans. But this Milk Bar birthday cake recipe cake instead instructs you to bake the cake batter in a sheet pan. You then use a cake ring to stamp out circles for different layers. It’s a new-to-me technique I wouldn’t have otherwise used in my own home baking! Very cool.

This recipe can easily be customized to fit within your schedule.

Real talk—I rarely make a layer cake all in one day. Typically, I make several (or all) of its components like the different cakes, fillings, and frostings beforehand before assembling the entire thing. Why? Leaving it all to do in one day easily sucks up the entire day. And I don’t have time for that! It’s much better to plan ahead, make certain things in advance, and save them for assembling later. You’ll find that when you do, a baking project that usually would have taken all day now only takes 30 minutes or less over the course of several days.

Because the Milk Bar birthday cake consists of FOUR different components total—cake, milk soak, frosting, and birthday cake crumbs—the only way to make it at home is to divide up the work over several days. Doing so results in a baking project that takes only 1 hour or less per day, resulting in an epic cake at the end! It makes it really easy to fit into a busy person’s schedule.

And by the way—if this sort of “recipe time management” is your thing, I highly suggest you check out my OWN cookbook, Weeknight Baking. I break down complicated, time-intensive recipes for layer cakes and pies this way so you can more easily fit it into your schedule!

photo of sliced milk bar birthday cake on cake stand

Ingredients And Substitutions

Now that I’ve convinced you to make the Milk Bar birthday cake, here’s everything you need for the recipe:

Shopping List for Milk Bar Birthday Cake Recipe

  • granulated sugar
  • light brown sugar
  • cake flour
  • rainbow sprinkles
  • baking powder
  • kosher salt
  • grapeseed oil
  • clear imitation vanilla extract
  • unsalted butter
  • vegetable shortening
  • large eggs
  • buttermilk
  • whole milk
  • cream cheese
  • confectioners’ sugar
  • light corn syrup
  • citric acid

And let’s talk about some key ingredients and their potential substitutions:

Cake Flour

You need ¾ cup cake flour to make the birthday cake crumbs, plus another 2 cups to make the birthday cake itself.

Cake Flour versus All-Purpose Flour

In the grocery store, you’ll likely find an aisle of more flour varieties than you would have thought existed: all-purpose, bread, cake, pastry, and many more. These varieties are defined by their protein percentages. 

Cake flour contains less protein than all-purpose flour. As a result, using cake flour in a cake recipe results in a cake with a softer and more tender crumb. If you need a brand recommendation, my favorite cake flour is Swans Down Cake Flour.

Can I use all-purpose flour instead of cake flour to make Milk Bar birthday cake?

Technically yes, but I don’t recommend it. In Momofuku Milk Bar, Christina writes that cake flour has a unique flavor that makes birthday cake *taste* like birthday cake!

Grapeseed Oil

You need ⅓ cup grapeseed oil to make the birthday cake.

Can I use another oil instead?

Yes! You can use whatever oil you have on hand instead. Canola oil, vegetable oil, and peanut oil work best to replace the canola oil because they are also neutral in flavors. 

Clear Imitation Vanilla Extract

You need lots of clear imitation vanilla extract to make all the components for this birthday cake recipe.

What is clear imitation vanilla extract?

In the Milk Bar cookbook, Christina explains that the secret to her funfetti cake is clear vanilla extract. 

What is clear vanilla extract? Most vanilla extracts are “pure”, meaning that they are made with real vanilla bean pods and are brown in color. Clear vanilla extract, on the other hand, is artificially made in a lab (hence the “imitation” in its name). Although it is vanilla in flavor, it’s not flavored by any actual vanilla beans. 

According to Christina, “it’s ‘vanilla’ in more of a guilty tub-of-frosting, box-cake way.” Indeed—using it in this homemade funfetti cake recipe gives the cake a more “authentic”, funfetti cake mix flavor. Additionally, its clear color keeps the cake crumb a bright white color that allows the sprinkles to really pop!

Where can I buy clear imitation vanilla extract?

You can find clear imitation vanilla extract in the baking aisles of any major grocery store like Kroger, Safeway, and more (Portlanders—Fred Meyer typically carries a variety of clear vanilla extracts!). It is usually by the pure vanilla extracts (although it is much cheaper than the real stuff). Christina writes that they use the McCormick brand at her bakery. I use Kroger’s generic version as well as the Watkins brand.

Can I use pure vanilla extract instead?

Yes, with reservations. Your cake will definitely taste great. However, your crumb won’t be as pale and white as mine. It might have a yellow-ish tinge.f

Citric Acid

You need a pinch of citric acid to make the frosting for this birthday cake recipe.

What is citric acid?

Citric acid is commonly used for flavor and a preservative in many foods like jams, jellies, sodas, and crunchy savory snacks like crackers and chips. It adds a sour, tart flavor to food, similar to the zestyness you would get from using lemon or lime. I’ve previously used it in this recipe for Tangy Meyer Lemon Sugar Cookies on Hummingbird High.

 You can learn more about the ingredient in this article by The Spruce Eats

Where do you buy citric acid?

You only need a pinch of citric acid for this recipe, so I suggest checking the bulk sections of any fancy grocery store, spice shop, or food co-op. I saw some in the bulk spice section at my Whole Foods and, if you live in Portland or the Bay Area, New Seasons. 

In a pinch, you can buy a giant bag for cheap on Amazon. You can also check the canning section of hardware or general stores. They usually sell citric acid by the canning tools and mason jars as it’s often used to help preserve jams and jellies. Just make sure that it’s labelled “food grade”. 

I don’t want to find/buy citric acid. Do I really need it? 

In a pinch, you can skip the citric acid. However, your frosting will likely be too sweet on its own—the citric acid helps balance it out. According to Christina, she did a bunch of research on how to recreate that canned frosting taste and found that citric acid was the “secret” ingredient to getting it right!

photo of sliced birthday cake on white plate with larger cake in background

How To Make Milk Bar Birthday Cake

Real Talk—to make this cake, you need to make four different recipes: one for the Birthday Cake Crumbs, another for the cake, the Birthday Cake Soak, and finally, the frosting. If you make all the components all at once, it’s going to take ALL day. Plus, you need to freeze the cake overnight after assembling it, then thaw it before serving. It’s definitely A PROJECT.

Luckily, many of the components can be made ahead of time. If you’re planning on serving the birthday cake for a special occasion on a weekend day like Saturday, I suggest following the schedule below.

Here’s a timeline on how to make Milk Bar birthday cake:

Day 1 (Wednesday): Make The Birthday Crumbs

However, note that the crumbs can be refrigerated for up to 1 month, and frozen for much longer.

To make the Birthday Crumbs, you’ll need to do the following:

  1. Prep the ingredients for the crumbs. (Prep Time: 5 minutes)
  2. Make the crumbs. (Work Time: 5 minutes)
  3. Bake the crumbs. (Bake Time: 20 minutes)
  4. Store the crumbs for assembling the layer cake.

Day 2 (Thursday): Make The Sheet Cake

In her cookbook, Christina states that you can refrigerate the cake overnight. However, I dislike refrigerating cakes because I find that it dries them out.

Instead, I recommend leaving it out at room temperature (tightly wrapped in two layers of plastic wrap) OR freezing it overnight. Freezing locks in the moisture of the cake. In a pinch, you can freeze the cake for up to 3 months!

To make the sheet cake, you’ll need to do the following:

  1. Prep the ingredients for the cake. (Prep Time: 5 minutes)
  2. Make the sheet cake. (Work Time: 15 minutes)
  3. Bake the sheet cake. (Bake Time: 30 minutes)
  4. Store the sheet cake for assembling the layer cake.

Day 3 (Friday): Make the Birthday Cake Soak and Frosting, Assemble The Layer Cake, Then Freeze Overnight

On this day, you’ll need to make the Birthday Cake Soak, the frosting, and assemble everything. Plan ahead for this one—it’s probably going to be the most labor-intensive day! 

Luckily, the Birthday Cake Soak comes together super quickly (all you need to do is whisk milk and vanilla together).

To make the Birthday Cake Soak, you’ll need to do the following:

  1. Prep the ingredients for the Birthday Cake Soak. (Prep Time: <5 minutes)
  2. Make the Birthday Cake Soak. (Work Time: <5 minutes) 

The frosting is a little more time-consuming. You need to beat it for a generous amount of time to get it light and fluffy. Even still, it only takes around 10 minutes or so to bring it together.

To make the frosting, you’ll need to do the following:

  1. Prep the ingredients for the frosting. (Prep Time: 5 minutes)
  2. Make the frosting. (Work Time: 10 minutes)

The bulk of the work happens when assembling the cake.

To assemble the cake, you’ll need to do the following:

  1. Prep the tools you need to make the layer cake. (Prep Time: 5 minutes)
  2. Use the cake ring to stamp out two 6-inch circles from the sheet cake, then reserve the remains for the first layer of the cake. (Work Time: 5 minutes)
  3. Make the first layer of the Milk Bar birthday cake. (Work Time: 10 minutes)
  4. Make the second layer of the Milk Bar birthday cake. (Work Time: 10 minutes)
  5. Make the final, top layer of the Milk Bar birthday cake. (Work Time: 5 minutes)
  6. Freeze the assembled cake.

Be sure to check out the recipe card below—it contains pictures of each step!

Day 4 (Saturday): Thaw the Cake, Then Serve and Enjoy!

After freezing the cake, you’ll need to pop the assembled cake out of its cake ring, then thaw for at least 3 hours in the refrigerator. I found it was still a little too chilled after 3 hours—I thawed it for an additional hour at room temperature before serving. 

close up photo of individual sliced birthday cake on a white plate with ridges

Recipe Troubleshooting and FAQ

FAQ: Baking Tools and Equipment To Make Milk Bar Birthday Cake

What baking tools do I need to make Milk Bar birthday cake?

To make this recipe, you need a handful of regular baking equipment and specialty baking equipment (which I’ve marked with an asterisk below):

And let’s talk about the specialty equipment below:

What is a quarter sheet pan? Can I use a 9 x 13-inch cake pan instead?

You need a quarter sheet pan to bake the Milk Bar birthday cake.

A quarter sheet pan has the same dimensions as a 9 x 13-inch rectangular cake pan. However, cake pans typically have 2- to 3-inch tall sides. In contrast, a quarter sheet pan typically only has short, 1-inch sides.

And yes! In a pinch, you can use a 9 x 13-inch cake pan instead and achieve the same results.

What is a cake ring? And do I really need one to make the cake?

A cake ring is often used in professional pastry kitchens to create mousse cakes and other fancy desserts. It looks like a cake pan, but with taller sides and no bottom. I used this cake ring to make my Milk Bar birthday cake. I like it because it has especially tall sides, and this recipe makes an especially tall cake! But there are plenty that you can choose from that are cheaper.

Unfortunately, you NEED a cake ring to make the Milk Bar birthday cake recipe. The closest substitution I could think of is to use the sides of a 6-inch springform pan (just make sure it has 2- to 3-inch tall sides, like this Fat Daddio’s or Wilton pan). However, because I’ve never tried it myself, I can’t guarantee the results!

Why can’t I use three 6-inch round cake pans to make the cake instead?

In the book, Christina Tosi instructs you to bake the cake batter into a sheet cake, use a cake ring to stamp out two 6-inch circles, then use the scraps for the base layer. More traditional recipes would instruct you to divide the batter into three 6-inch cake pans to make the three different layers.

Truthfully, I really have no idea why Christina Tosi instructs you to do it that way in her book. My hunch is that, in a professional bakery, this process makes more space in the kitchen (cake pans are bulkier to store than sheet pans) and they’re able to repurpose the scraps for other baked goods (like their cake truffles).

But I guess if you want to make your life a little bit easier, go ahead and divide the cake batter into three 6-inch cake pans and bake it that way. Just make sure to do it evenly because this cake is unforgiving. Since it’s naked, you’ll be able to see any uneven layers in the final cake. I would even weigh the batter with a scale before dividing it.

How? I place a bowl on my digital kitchen scale, tare it, then pour the batter into the bowl. I divide the resulting number by three (say, the cake batter weighs 300 grams total), then pour the resulting number into three 6-inch cake pans (in my example, 100 grams per pan), using the scale to weigh everything out once more.

Note that, even if you go this route, you’ll STILL need the 6-inch cake ring to build and assemble the cake. Sorry!

What is acetate paper?

Acetate paper is clear paper made out of plastic. In baking, it functions like parchment paper. Professional pastry chefs line the inside of cake pans and molds with the acetate paper to form the cake, then peel it off before serving. It is stiffer and less adhesive than parchment paper, making it a great tool for making cakes with melty and liquidy fillings like creams, curds, ice creams, and mousse.

The Best Acetate Paper for the Milk Bar Birthday Cake Recipe

When the Momofuku Milk Bar cookbook first came out in 2011, acetate paper wasn’t widely available outside of pastry kitchens. Instead, you had to order it online from Amazon, where the acetate was sold in sheets similar to printer paper (since acetate is also used for projector slides). These days, Amazon has a much wider selection of acetate sheets for baking. You can get acetate cake collars easily, which are already cut and shaped into the right dimensions for baking.

In the book, Christina Tosi writes that you need two rectangular sheets of acetate paper to make the cake, each 20 inches long and 3 inches tall. You can cut a sheet of acetate paper to that size, or buy a roll of a 3-inch or a 4-inch inch tall acetate cake collar paper and cut a 20-inch length of it. The height of the cake collar doesn’t matter too much—you can even buy a 6-inch or an 8-inch tall roll, which will work well with the recipe since the resulting cake is around 6 inches tall.

However, there are pros and cons. Using a taller roll of acetate paper will eliminate the need to use the two cake collars as instructed in the recipe below. However, it will also make it much harder to build the base and second layer. The taller sides of the acetate paper will get in the way as you try and spread the passion fruit curd and coffee frosting on the different layers!

FAQ: Storing Milk Bar Birthday Cake for Serving Later

How To Store Milk Bar Birthday Cake

The assembled cake will keep, uncovered in the refrigerator, for up to 1 day. After that, tightly wrap in plastic wrap and refrigerate for an additional 3 days. Leftover slices can be stored in an airtight container in the fridge.

Can you freeze Milk Bar birthday cake?

Yes! You can freeze Milk Bar birthday cake in two ways.

First, you can freeze the assembled cake (still in its cake ring on a sheet pan) for up to 2 weeks. When ready to serve, follow the recipe instructions to thaw the cake in the refrigerator and serve accordingly.

Second, you can freeze any leftover slices. Tightly wrap any leftover slices in two layers of plastic wrap and a layer of aluminum foil if storing for longer than 1 week. Freeze for up to 3 months. To serve, thaw in the refrigerator overnight.

Best Recipe Tips

Best Tips for Making the Sheet Cake

  • In the cookbook, Christina Tosi warns that there is a ton of liquid and fat in the birthday cake base. She encourages you to make sure that the batter is homogenous at each step (meaning no streaks, discolorations, or any other signs of separation and unincorporation). In fact, the book specifically states that you need to mix the batter on medium-high for AT LEAST 4 to 6 minutes, or until the mixture is “practically white, twice the size of the original fluffy butter-and-sugar mixture, and completely homogenous.” Don’t rush the process!

  • This funfetti cake recipe is unusual in that it instructs you to use whole eggs as opposed to just egg whites to make the batter. If you use eggs that have an especially orange yolk, your crumb might come out yellow instead of white. Counteract this by adding 1 to 2 drops of blue or purple food coloring to the batter—this will make the crumb more white!

Best Tips For Assembling the Milk Bar Birthday Cake

  • In the original recipe, Christina Tosi instructs you to assemble the cake with two acetate cake collars, each roughly around 20 inches long and 3 inches tall. These days, you can easily buy acetate cake collar rolls that are taller and measure either 6 or 8 inches in height. Truthfully, these rolls suit the recipe much better since the resulting cake is around 6 inches tall. So if you opt for a taller cake collar roll, you’ll only need to use one cake collar for the whole cake! But there are some disadvantages to doing so—checkout the Troubleshooting and FAQ section of the blog post for more info!

  • The original recipe is also pretty vague about dividing up the Birthday Cake Crumbs, Birthday Cake Soak, and frosting between the layers. The book only gives you rough estimates (e.g. “Use half of the Birthday Cake Soak for the bottom layer”) as opposed to giving you exact volume or weight measures for each layers. So the first time I made this cake, it was wildly uneven! I ended up using way more frosting for the first layer, and ran out by the time I needed to frost the rest of the cake. Similarly, I used way too much soak and crumbs in my bottom layer versus the middle layer.

    So when adapting this recipe for Hummingbird High, I made sure to give you EXACT weight measures of the different components needed for each layer. Doing so ensures an even, perfect cake with just the right textures and quantities for each layer! I mean, truthfully, you can probably just eyeball it too. But why not just strive for perfection?

  • After freezing the cake, the recipe instructs you to pop it out of its cake ring before thawing in the refrigerator. Doing so actually more difficult than I anticipated! The acetate cake collar was frozen around the cake ring. I ended up taking an offset spatula and running it between the acetate and the cake ring. I then pressed my fingers around the outside of the cake, rotating it to methodically apply gentle pressure all around.

More Epic Layer Cakes

Get the Recipe: Milk Bar Birthday Cake Recipe

This Milk Bar Birthday Cake Recipe is a homemade version of the most popular cake from famed New York City bakery, Milk Bar! The birthday cake is made with layers of white cake studded with rainbow sprinkles, cream cheese frosting, and a crunchy streusel made from birthday cake crumbs.
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Ingredients

For the Birthday Cake Crumb

  • ½ cup (3.5 ounces or 99 grams) granulated sugar
  • 1 ½ Tablespoons (.75 ounces or 21 grams) tightly packed light brown sugar
  • ¾ cup (3 ounces or 85 grams) cake flour
  • 2 Tablespoons (.75 ounces or 21 grams) rainbow sprinkles
  • ½ teaspoon baking powder
  • ½ teaspoon kosher salt
  • ¼ cup (2 ounces or 57 grams) grapeseed oil
  • 1 Tablespoon clear imitation vanilla extract

For the Birthday Cake

  • 2 cups (8 ounces or 227 grams) cake flour
  • ¼ cup plus 2 Tablespoons (2.25 ounces or 64 grams) rainbow sprinkles, divided into ¼ cup (1.5 ounces or 43 grams) and 2 Tablespoon (0.75 ounces or 21 grams) portions
  • 1 ½ teaspoons baking powder
  • ¾ teaspoon kosher salt
  • ¼ cup (½ stick or 2 ounces or 57 grams) unsalted butter, at room temperature
  • cup (2.15 ounces or 60 grams) vegetable shortening
  • 1 ¼ cups (8.75 ounces or 248 grams) granulated sugar
  • 3 Tablespoons tightly packed (1.45 ounces 41 grams) light brown sugar
  • 3 large eggs, at room temperature
  • ½ cup (4 ounces or 113 grams) buttermilk, at room temperature
  • cup (2.35 ounces or 67 grams) grapeseed oil
  • 2 teaspoons clear imitation vanilla extract

For the Birthday Cake Soak

  • ¼ cup (2 ounces or 57 grams) whole milk
  • 1 teaspoon clear imitation vanilla extract

For the Birthday Cake Frosting

  • 1 ¼ cups (5 ounces or 142 grams) confectioners' sugar, sifted if necessary
  • ½ teaspoon kosher salt
  • pinch of baking powder
  • pinch of citric acid
  • ½ cup (1 stick or 4 ounces or 113 grams) unsalted butter, at room temperature
  • ¼ cup (1.75 ounces or 50 grams) vegetable shortening
  • ¼ cup (2 ounces or 57 grams) cream cheese, at room temperature
  • 2 Tablespoons (1.5 ounces or 43 grams) light corn syrup
  • 1 Tablespoon clear imitation vanilla extract

Equipment

  • parchment paper
  • an airtight container
  • a stand mixer with a paddle attachment
  • a bench scraper
  • a 9 x 13-inch quarter sheet pan
  • a 6-inch cake ring with 2-inch OR 3-inch tall sides
  • acetate paper, cut into one 20-inch long x 6-inch tall rectangular strip OR cut into two 20-inch long x 3-inch tall rectangular strips
  • a pastry brush

Instructions
 

Day 1: Make the Birthday Cake Crumb Recipe

  • Prep the oven and baking pan. Position a rack in the center of the oven and preheat the oven to 300°F. Line a quarter sheet pan with parchment paper.
  • Mix the dry ingredients. In a medium bowl, whisk together the sugars, flour, sprinkles, baking powder, and salt.
  • Whisk the wet ingredients. In a small liquid measuring cup, whisk together the oil and vanilla.
  • Mix the wet ingredients into the dry ingredients. Slowly pour the wet ingredients into the dry ingredients. Mix with a rubber spatula until the mixture starts to come together in small clusters and crumbs.
  • Bake the crumbs. Use a rubber spatula to spread the clusters on a parchment-lined sheet pan.
    Bake for 20 minutes, using a bench scraper to break them up every 4 to 5 minutes. After 20 minutes, the crumbs should still be slightly most to the touch at that point. They will harden and dry as they cool.
  • Store for assembling the layer cake. Cool the crumbs in the pan on a wire rack completely before storing or using in the recipe.
    The crumbs will keep, in an airtight container at room temperature, for up to 1 week. The crumbs will also keep, in an airtight container in the refrigerator, for up to 1 month.

Day 2: Make The Birthday Cake Recipe

  • Prep the oven and cake pan. Position a rack in the center of the oven and preheat the oven to 350°F.
    Generously spray a quarter sheet pan with cooking spray and line the bottom with parchment paper, leaving a 2-inch overhang on the pan's two long sides. Spray the parchment, too.
  • Mix the dry ingredients. In a medium bowl, whisk together the flour, ¼ cup (1.5 ounces or 43 grams) of sprinkles, baking powder, and salt.
  • Beat the butter, shortening, and sugars. In the bowl of a stand mixer fitted with the paddle attachment, combine the butter, shortening, and sugars. Beat on medium until light, fluffy, and doubled in volume, 3 to 4 minutes, using a rubber spatula to scrape down the bottom and sides of the bowl as necessary.
  • Add the eggs, oil, buttermilk, vanilla, and dry ingredients. Reduce the mixer to low and add the eggs one at a time, adding the next egg only after the previous one has been fully incorporated, scraping down the bottom and sides of the bowl after each addition.
    With the mixer on low, slowly pour in the buttermilk, followed by the oil and vanilla, and beat until the mixture is smooth, 4 to 6 minutes.
    Gradually add the dry ingredients and beat until just combined. Scrape down the bottom and sides of the bowl once more, and beat on low for an additional 30 seconds.
  • Assemble the cake for baking. Pour the batter into the prepared pan and use an offset spatula to smooth its top if necessary. Sprinkle the remaining 2 Tablespoons of sprinkles (0.75 ounces or 21 grams) evenly over the batter.
  • Bake the cake. Bake for 30 to 35 minutes. When done, the top of the cake should bounce back when gently pressed and a skewer inserted into the center of the cake should come out with a few crumbs attached.
  • Store for assembling the layer cake. Cool completely in the pan on a wire rack before storing or using for assembly.
    Turn the cake out onto a sheet of plastic wrap. Use the plastic wrap to tightly wrap the entire cake (you may need an additional sheet or two of plastic wrap to cover it completely).
    The cake will keep, at room temperature, for up to 1 day. The cake will also keep in the freezer, wrapped in an additional layer of aluminum foil, for up to 3 months.

Day 3: Make The Birthday Cake Soak Recipe

  • Whisk the wet ingredients. In a small liquid measuring cup, whisk together the milk and vanilla.

Day 3: Make The Birthday Cake Frosting Recipe

  • Whisk the dry ingredients. In a medium bowl, whisk together the confectioners' sugar, salt, baking powder, and citric acid.
  • Beat the butter, shortening, and cream cheese. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, shortening, and cream cheese on medium-high until smooth and creamy, about 2 to 3 minutes.
  • Scrape down the bottom and sides of the bowl, then add the corn syrup and vanilla. Scrape down the bottom and sides of the bowl with a rubber spatula. With the mixer on low, add the corn syrup and vanilla. Beat on medium until combined, about 2 to 3 minutes.
  • Add the dry ingredients, and beat on medium-high until creamy and smooth. Scrape down the bottom and sides of the bowl. With the mixer on low, gradually add the dry ingredients. Beat on medium-high until combined, about 2 to 3 minutes. Use immediately.

Day 3: Assemble The Birthday Cake

  • photo of hands lifting a cake out of a sheet pan
    First, prep the birthday cake for cutting. Use the overhanging parchment as handles to lift the brownies out of the pan and onto a cutting board.
  • photo of hands cutting out sheet cake with a cake ring
    Cut the sheet cake into the different layers. Use the cake ring to stamp out 2 full circles and 2 half circles from the cake.
  • A photo of sheet cake sliced into cake layers
    The full circles will be your top two cake layers, while the half circles and remaining cake scraps will come together to make the bottom layer of the cake.
  • photo of cake ring lined with acetate on sheet pan
    Prep the cake ring and acetate cake collar. Clean the cake ring and place it in the center of a sheet pan lined with clean parchment paper. Line the inside of the cake ring with the acetate paper (if using two strips of acetate paper, just use one strip).
  • photo of cake ring filled with two birthday cake halves
    Make the bottom layer. Nestle the two half circles in the cake ring, pressing their round sides against the cake ring. There will be a gap in the middle of the circles—this is totally okay, I promise!
  • photo of bottom layer of milk bar birthday cake while being assembled
    Fill the gap between the two half circles with the remaining cake scraps. Use the back of your hand to press the scraps together to fit into the space. Head's up that you're going to have more scraps than can fit in the gap—that's totally normal, I promise! Simply take the excess scraps and press them down evenly on top of the rest of the cake layer, using the back of your hand to create a flat and even layer.
    At this point, the acetate collar will start to wrinkle from the pressure of the cake. Don't worry about it too much! It will even back out when you add the middle and top layer.
  • Photo of Milk Bar birthday cake being assembled with cake soak
    Brush the bottom layer with half of the Birthday Cake Soak. Use a pastry brush to brush half of the Birthday Cake Soak for assembly over the layer.
    If using a digital scale to weigh out the soak, you'll need approximately 1 ounce (30 grams) of Birthday Cake Soak for this layer.
  • photo of milk bar birthday cake being assembled with frosting
    Spread a third of the Birthday Cake Frosting over the soaked cake. Use the back of a spoon or a small rubber spatula to spread ⅓ of the Birthday Cake Frosting as evenly as possible over the soaked cake If using a digital scale to weigh out the frosting, you'll need approximately 5 ounces (142 grams) of frosting for this layer.
  • photo of milk bar birthday cake being assembled with frosting
    Don't worry too much about making the top of the frosting smooth—you'll cover it with other ingredients in the next step. The more important thing is to try and spread it as evenly as you can across the top of the cake, and ensure that too much of it doesn't get up on the sides of the acetate collar.
  • photo of milk bar birthday cake being assembled with crumbs
    Sprinkle a third of the Birthday Cake Crumbs over the frosted cake. Sprinkle a third of the Birthday Cake Crumbs over the frosted cake.
    If using a digital scale to weigh out the crumbs, you'll need approximately 3 ounces (85 grams) of crumbs for this layer.
  • photo of milk bar birthday cake layer full of crumbs
    Use the back of your hand to gently press the crumbs in place. If you want to go the extra mile, sprinkle slightly more crumbs along the outer edges of the cake. Christina Tosi recommends doing so in a YouTube tutorial of hers—doing so creates more contrast between layers in the final, assembled cake!
  • photo of middle layer of milk bar birthday cake being assembled
    Make the middle layer. If you're using two acetate cake collars, gently tuck the second strip of acetate between the cake ring and the top ¼ inch of the first strip of acetate. Doing so creates a ring of acetate that is 5 to 6 inches tall, combined—this will be high enough to support the height of the finished cake.
    Set a cake round on top of the Birthday Cake Crumbs. If one of your cake rounds is jankier than the other, use it in the middle and save the pretty one for the top!
  • Photo of Milk Bar birthday cake being assembled with cake soak
    Repeat the process for brushing the middle layer with the remaining half of the Milk Bar soak. Use a pastry brush to brush the remaining half of the Birthday Cake Soak over this cake.
  • photo of milk bar birthday cake being assembled with frosting
    Repeat the process for frosting the soaked cake with a third of the Birthday Cake Frosting. Use the back of a spoon or a small rubber spatula to spread ⅓ of the Birthday Cake Frosting as evenly as possible over the soaked cake.
    If using a digital scale to weigh out the frosting, you'll need approximately 5 ounces (142 grams) of frosting for this layer.
  • photo of milk bar birthday cake being assembled with crumbs
    Repeat the process for sprinkling a third of the Birthday Cake Crumbs over the frosted cake. Sprinkle a third of the Birthday Cake Crumbs over the frosted cake.
    If using a digital scale to weigh out the crumbs, you'll need approximately 3 ounces (85 grams) of crumbs for this layer.
  • photo of middle layer of milk bar birthday cake being assembled
    Make the top layer. Set the final cake round on top of the Birthday Cake Crumbs.
  • photo of milk bar birthday cake being assembled with frosting
    Repeat the process for frosting the cake with the remaining Birthday Cake Frosting. Use the back of a spoon or a small rubber spatula to spread the remaining ⅓ of the Birthday Cake Frosting as evenly as possible over the cake.
    If using a digital scale to weigh out the frosting, you'll need approximately 5 ounces (142 grams) of frosting for this layer.
  • photo of milk bar birthday cake being assembled with crumbs
    Repeat the process for sprinkling the remaining third of the Birthday Cake Crumbs over the frosted cake. Sprinkle a third of the Birthday Cake Crumbs over the frosted cake.
    If using a digital scale to weigh out the crumbs, you'll need approximately 3 ounces (85 grams) of crumbs for this layer.
    I like to leave a little circle of frosting in the center of the cake for "aesthetic"—however, you can cover the frosting completely if you'd like!
  • Freeze the cake. Transfer the sheet pan with the cake to the freezer. Freeze, uncovered and fully assembled, for a minimum of 12 hours to set the cake and all its fillings. The cake will keep in the freezer for up to 2 weeks.

Day 4: Serve and Store

  • Thaw the cake, then serve. At least 3 hours before you are ready to serve the cake, pull the sheet pan out of the freezer and use your fingers and thumbs to gently pop the cake out of the cake ring.
    Transfer the cake to a serving plate or cake stand. Gently peel off the acetate. Defrost in the fridge for a minimum of 3 hours (or 1 hour at room temperature) before serving.
  • Store the cake. The assembled cake will keep, uncovered in the refrigerator, for up to 1 day. After that, tightly wrap in plastic wrap and refrigerate for an additional 3 days. Leftover slices can be stored in an airtight container in the fridge.

Notes

  • In the cookbook, Christina Tosi warns that there is a ton of liquid and fat in the birthday cake base. She encourages you to make sure that the batter is homogenous at each step (meaning no streaks, discolorations, or any other signs of separation and unincorporation). In fact, the book specifically states that you need to mix the batter on medium-high for AT LEAST 4 to 6 minutes, or until the mixture is “practically white, twice the size of the original fluffy butter-and-sugar mixture, and completely homogenous.” Don’t rush the process!  
  • This funfetti cake recipe is unusual in that it instructs you to use whole eggs as opposed to just egg whites to make the batter. If you use eggs that have an especially orange yolk, your crumb might come out yellow instead of white. Counteract this by adding 1 to 2 drops of blue or purple food coloring to the batter—this will make the crumb more white!  
  • In the original recipe, Christina Tosi instructs you to assemble the cake with two acetate cake collars, each roughly around 20 inches long and 3 inches tall. These days, you can easily buy acetate cake collar rolls that are taller and measure either 6 or 8 inches in height. Truthfully, these rolls suit the recipe much better since the resulting cake is around 6 inches tall. So if you opt for a taller cake collar roll, you’ll only need to use one cake collar for the whole cake! But there are some disadvantages to doing so—checkout the Troubleshooting and FAQ section of the blog post for more info!  
  • The original recipe is also pretty vague about dividing up the Birthday Cake Crumbs, Birthday Cake Soak, and frosting between the layers. The book only gives you rough estimates (e.g. “Use half of the Birthday Cake Soak for the bottom layer”) as opposed to giving you exact volume or weight measures for each layers. So the first time I made this cake, it was wildly uneven! I ended up using way more frosting for the first layer, and ran out by the time I needed to frost the rest of the cake. Similarly, I used way too much soak and crumbs in my bottom layer versus the middle layer. So when adapting this recipe for Hummingbird High, I made sure to give you EXACT weight measures of the different components needed for each layer. Doing so ensures an even, perfect cake with just the right textures and quantities for each layer! I mean, truthfully, you can probably just eyeball it too. But why not just strive for perfection?  
  • After freezing the cake, the recipe instructs you to pop it out of its cake ring before thawing in the refrigerator. Doing so actually more difficult than I anticipated! The acetate cake collar was frozen around the cake ring. I ended up taking an offset spatula and running it between the acetate and the cake ring. I then pressed my fingers around the outside of the cake, rotating it to methodically apply gentle pressure all around.
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Weeknight Baking:
Recipes to Fit your Schedule

Over the past several years of running Hummingbird High, I kept a crucial aspect of my life hidden from my readers: I had a full-time, extremely demanding job in the tech world. In my debut cookbook, Weeknight Baking, I finally reveal the secrets to baking delicious desserts on a tight schedule.