It’s my 31st birthday tomorrow and I’m celebrating with a re-do of my 30th birthday (which I cancelled last year because I stupidly decided to hold my book auction that day and it was traumatizing; also, it was supposed to be a picnic and it rained). We’re starting off with a meal with Erlend’s parents at Ava Gene’s and karaoke jello shots with a small group of friends. Then on Sunday, Lauren of @lokokitchen pie fame and I are getting brunch and talking about our upcoming pie class at Feast (tickets sold out within 10 minutes, THANK YOU TO ANYBODY WHO BOUGHT ONE, I still can’t believe it)! I only hope I’ll be in okay shape for it (unlike last weekend, where I accidentally had too many cocktails at a tiki cocktail making class at House Spirits, blitzed my way through my college reunion, then found myself at a media brunch taste testing biscuits for an upcoming article with Eater — woo!).
Let me make this super quick, because it’s Friday and I know you have better things to do: if you follow me on Instagram, you’ll know that this was originally supposed to be a banana birthday cake, lol. Similar to the lime fiasco of last month (in which I accidentally bought 10lbs worth of limes from Costco before remembering I’d already developed the key lime pie recipe for #weeknightbakingbook and subsequently had to get rid of them by throwing an impromptu margarita party), I found myself with 10lbs of extra bananas after the recipe development for the banana cream pie went by super quickly. It turns out banana pie is really really good (soweeee Molly) and doesn’t really need too much tinkering beyond adding a cookie crumb crust, say whattttt.
So I was determined to make myself a banana cake (especially after a bite of Palomar’s rum-soaked banana cake at the Feast launch party this past week, yum) with the leftover bananas, but then found myself with with 6 extra egg yolks leftover from a lemon meringue pie #weeknightbaking book shoot. That seemed to me like a sign from the baking gods telling me that yellow cake was the way to go, especially since bananas freeze well in a way that egg yolks do not.
So let’s talk about this cake! Remember how a few years ago, galaxy desserts were all the rage? I was recently reminded of this as I was reading a recent pop science article about how new stars turn galaxies pink. The pretty photos of the pink stars inspired this buttercream design because I have this weird thing about turning natural phenomena into cakes (see: this bomb cyclone cake and that cherry blossom cake).
But really, I’m mostly excited about the cake because underneath all that pink and magenta frosting is the tastiest yellow cake you’ll ever eat. At first glance, it seems like it uses a scary number of egg yolks (8 total!), but don’t panic. I’m not going to leave you with a bowl of egg whites to eat throughout the week for sad, healthy omelettes (or at least, that’s what I reluctantly do with all my leftover egg whites). Instead, I’ve been on a Swiss meringue buttercream kick ever since making my friend’s feminist birthday cake last week — usually, I find Swiss meringue buttercream to be a pain the butt because a standard recipe requires so many egg whites. In this case, it actually makes the perfect companion to this yellow cake since it uses up most of leftover egg whites from the cake recipe! Since I had a ton of leftover strawberries, blueberries, and cherries from various #weeknightbakingbook projects, I spiked the buttercream with fruit puree for some subtle summertime flavor. Enjoy!
- Okay, if you looked at the yellow cake recipe and got scared off by the number of yolks required (which again you will be needing for the frosting, so really, this panic is unnecessary, but whatever, I get it), you can substitute 3 large whole eggs for the 8 egg yolks and still make a perfectly good yellow cake! If you go that route, you’ll need 6 large whole eggs total for the cake recipe.
- Because I was baking for a crowd, this cake is bigger than what I usually prefer and bake for myself. In retrospect, I probably should have baked the recipe in three 9-inch pans as opposed to 8-inch ones. You can still opt for 8-inch pans, but just make sure they have tall sides that are at least 3-inches; Amazon has a great selection.
- This recipe uses Swiss meringue buttercream frosting, which can be time consuming and finicky to make but produces a silky frosting that is a dream to pipe. For this recipe, it’s important that all your ingredients are at the temperature required for the recipe, especially the butter and berries. If you add cold berries to the buttercream, there’s a chance that the frosting can curdle and separate. To ensure that this won’t happen, I actually zap the berries in the microwave for 15 seconds just to make sure that they’ll fully incorporate. If you find your frosting curdling, no worries! Microwave a rough 1/4 cup (you can eyeball it) of the frosting in a separate bowl for about 30 seconds, or until its melted and liquidy, warm but not hot/boiling. With the mixer on low speed, add the melted frosting back into the larger batch — that should fix any curdling! If you have the opposite problem and your frosting is too liquidy, stick the entire batch in the fridge for 10 minutes to stiffen, then beat on medium speed for 3 minutes until silky smooth. As for the berries themselves, I used a mix but recommend you just commit to one fruit that’s super ripe and juicy (I recommend strawberries — I initially tried cherries, but found them to be too dry and flavorless); using the mix I did sorta drowned out an overall flavor.
- To decorate the cake, I first layered the cakes and crumb coated the entire thing for a solid foundation. I then divided the leftover frosting into three batches, dying each a varying shade of pink from this awesome Americolor food coloring set. I then put dollops of the shades of pink randomly across the cake, before frosting the entire thing smooth. I think this is called the watercolor technique? Tessa, one of my best baking buddies, has a great tutorial on how to do it, complete with super helpful GIFs. After the frosting set, I used my fingers to press edible gold leaf and gold leaf stars randomly across the cake. Woohoo!
Pink Galaxy Birthday Cake
- Special Equipment: a food processor
- a candy thermometer (preferably digital)
For the Yellow Cake
- 3 cups (12 ounces) cake flour
- 2 teaspoons baking powder
- 1 1/2 teaspoons kosher salt
- 1 cup (8 ounces) unsalted butter, at room temperature
- 2 1/2 cups (17.5 ounces) granulated sugar
- 1/2 cup (3.75 ounces) tightly packed dark brown sugar
- 8 large egg yolks, at room temperature (be sure to reserve the whites for the buttercream frosting!)
- 3 large eggs, at room temperature
- 1 cup 8 ounces buttermilk, at room temperature
- 1 cup 8 ounces canola oil
For the Berry Buttercream Frosting
- 6 ounces fresh berries, at room temperature (see bakers notes)
- 1 teaspoon pure vanilla extract
- a pinch of kosher salt
- red food coloring
- 2 tablespoons granulated sugar plus 2 cups (14 ounces) granulated sugar, divided into 2 tablespoon and 2 cup portions
- 1 cup 8 ounces large egg whites from about 8 eggs
- 3 cups 24 ounces unsalted butter, at room temperature
For the Yellow Cake
- Center a rack in the oven and preheat to 350 (F). Prepare three 8 x 3-inch cake pans by spraying each pan generously with cooking spray and lining the bottom of each pan with parchment paper. Spray the parchment paper as well and set aside.
- In a medium bowl, whisk together cake flour, baking powder, and salt. Set aside.
- In the bowl of a freestanding electric mixer fitted with a paddle attachment, combine butter and sugars. Beat on medium speed for 3 to 4 minutes, or until light, fluffy, and doubled in volume. Reduce the mixer speed to its lowest setting and add egg yolks, two at a time, only adding the next pair when the previous one is fully incorporated. Add 3 large eggs, one at a time, only adding the next egg when the previous one is fully incorporated. Once all the eggs are added, slowly stream in the canola oil, followed by the buttermilk and vanilla. Continue beating on low speed until the mixture is homogeneous and there are no lumps, about 3 to 4 minutes. With the mixer still on its lowest setting, add the dry ingredients all at once and keep beating just until the dry ingredients disappear into the batter, another 30 to 45 seconds.
- Use a rubber spatula to scrape down the sides of the bowl and pour the batter into the prepared cake pans. Transfer to the preheated and oven and bake 40 to 45 minutes. When done, the top of the cake should be golden and bounce back when gently poked. A skewer inserted into the center of the cake should come out with few crumbs. Transfer to a wire rack and cool completely before frosting.
For the Berry Buttercream Frosting
- In the bowl of a food processor, combine fresh berries, 2 tablespoons granulated sugar, vanilla extract, and a pinch of kosher salt. Process until the fruit turns into a fine puree; pour into a liquid measuring cup, measuring out a 3/4 cup portion, and discard the remaining puree (or, save for another project!). If your puree has turned out an unattractive brown color, add a few drops of red food coloring and process until the puree has turned a more attractive pink color. Set aside.
- Combine the egg whites and the remaining 2 cups granulated sugar in the bowl of a freestanding electric mixer. Whisk the ingredients together, and then use a rubber spatula to scrape down the sides of the bowl. Fill a medium saucepan with a few inches of water and place over medium-high heat. Place the mixer bowl on top of the saucepan to create a double boiler; the bottom of the bowl should not touch the water.
- Whisking intermittently, cook the egg and sugar mixture until it registers 160 (F) on a candy thermometer, scraping down the sides of the bowl with a heatproof rubber spatula occasionally to prevent any burning. Once hot, carefully transfer to the stand mixer and fit a whisk attachment onto the mixer. Beat the egg white mixture on high speed for 8 to 10 minutes, until it holds medium-stiff peaks. When done, the outside of the mixer bowl should be at room temperature and no residual heat should be escaping the meringue out of the top of the bowl. Stop the mixer and swap out the whisk attachment for the paddle attachment.
- With the mixer on low speed, add butter a few tablespoons at a time, scraping down the sides of the bowl every so often to make sure the butter is incorporating fully. Once incorporated, turn up the mixer speed to medium-high and beat until the buttercream is silky smooth, 3 to 5 minutes. Reduce the mixer speed to the lowest setting. Gradually add the reserved fruit puree to the buttercream, mixing until combined.