GIF of 9 x 13 inch cookie cake

This 9 x 13 inch cookie cake recipe is based on the popular chocolate chip cookie from my cookbook, Weeknight Baking (and also seen online in My Best Easy Chocolate Chip Cookie Recipe).

Instead of scooping the dough to make individual cookies, I instruct you to bake the dough in a quarter sheet pan (9×13 inches). Doing so makes a sliceable cookie cake that’s ideal for birthdays, parties, or last-minute dessert cravings that aren’t too time intensive in the kitchen!

The best part? The cookie cake slices taste like your favorite chocolate chip cookie. Think: fudgy centers, crispy edges, lots of chocolate. When paired with a quick and easy American buttercream frosting, it tastes exactly like the mall cookie cake from your childhood memories!

Looking for a traditional round chocolate chip cookie cake? Check out My Best Chocolate Chip Cookie Cake Recipe!

I made this cookie cake for Hummingbird High‘s 14th birthday. Learn more below, or skip right to the recipe!

photo of rectangular chocolate chip cookie cake sliced into squares

A Note About Hummingbird High’s 14th Anniversary

It’s been about a year since I checked in on Hummingbird High‘s 13th Anniversary and my 2024 recap. And oh boy, how much things have changed since then!

When we last spoke, I told y’all about my transition away from Hummingbird High as my full-time endeavor and my return to the corporate world. I had several reasons for doing so: I was worried about the future of blogging and content creation, and I’d lost my love for the game. I thought that no longer relying on this blog for money would give me creative freedom again.

I’d foolishly thought that returning to the corporate world would also give me stability that working as a content creator did not. But I was in for a nasty surprise. The tech industry I’d returned to was plagued with instability, thanks to a shaky economy and the threat of AI replacing us all (more on that shortly). After just three months at my new job, a competitor bought out the company with plans to gut the company and lay everybody off.

The prospect of losing my “stable” income immediately derailed my plans to make Hummingbird High completely my own again. To make sure I had a financial safety net in the advent of a corporate layoff, I found myself returning to the SEO tactics that made me question my love for this space in the first place.

And let me tell you—SEO strategy has gotten even tougher thanks to AI. I now had to scour my old posts to get rid of filler content (a.k.a. information that I found interesting and wanted to share, the stuff that gave my posts personality) and remove links to old friends’ blogs lest it be considered spam. All of this was because creators were now officially competing with generative AI, a tool that apparently gives users exactly what they want without having to wade through human yapping. So in order to survive, I had to make sure my work was more like AI’s output (or, slop).

Dark.

I then spent many months going through old blog posts in my spare time, editing and deleting original writing and content I still found valuable. It was all in the hopes that my recipes would continue to show up in Google and I wouldn’t go into some kind of financial destitution between my potential layoff and Hummingbird High‘s declining traffic. It was boring, tedious, and depressing work. The worst part? I genuinely couldn’t tell if it was even moving the needle.

So at first I treated my work with respect, lovingly combing through paragraphs, saving information for later, critically reviewing passages to edit them down while maintaining their essence. But after weeks of this thankless work, the malaise set in: I found myself unironically copy-and-pasting my blog posts into ChatGPT, asking it to edit my work to “be more like ChatGPT”. What all of this did was officially turn my declining enthusiasm for blogging to outward, unbridled HATE. I began dreading anything related to Hummingbird High. Even the act of baking and developing recipes, now relegated to the weekends and once my source of joy, became just another chore to deal with.

But then, lighting in a bottle! I landed a new corporate job before my old company officially shut down (how I pulled this off felt like I’d cashed in all the luck in my lifetime, and it’s a story for another day). I’ve officially been at this company for almost 5 months now, and still can hardly believe how it worked out. And with a steady paycheck again, I could continue my original plans for Hummingbird High… right?

No, not exactly.

I cannot overstate the damage that those dark months of “AI-ifying” Hummingbird High did to my psyche. Because as I dutifully whittled down my past work, I kept catching glimpses of a bleak future—one where efficiency trumped individuality and lived experience, one where we just make things to please the machines (in addition to toddlers and drunk people).

It also doesn’t help that my new corporate job puts me in the trenches of understanding AI technology and its capacity to replace us all. So do I think that AI will replace us? No, not really, most of what it generates is slop. But here’s the rub: it turns out a lot of people are okay with slop! In fact, many prefer an instant slop-ified answer over the inconvenience of having to scroll a few seconds longer to get to something better. And although this kind of thinking will likely get me left behind of whatever cursed AI arms race content creators are in, I truly believe I shouldn’t have to diminish my content to “compete” with this slop!

And now, with a steady paycheck from my new corporate job, I don’t have to anymore, either.

So what does that mean for Hummingbird High? I don’t really know. I sometimes daydream of ghosting this space, leaving folks to wonder what happened, similar to how big baking creators of yesteryear have done (anybody remember Stella Parks?). But that doesn’t seem enough.

Because a lot of the time, I want to just blow to it all up. Let’s delete EVERYTHING, scorched earth style! If I lost Hummingbird High, none of you LLM bots can use my site to train your models to generate the slop that drove me out of existence! And none of you AI sloppers can have my recipes either—especially when you discover just how bad ChatGPT’s recipes actually are! Hummingbird High will die on my terms, lost forever but undefeated in this small way!

Or not, because I’m also just too tired and sad to do anything major. And that’s okay too.

There are still days though, in which I dream of eating sweets in my head like these Swirled Thai Tea Cookies with Condensed Milk and find myself disappointed that nobody’s developed anything like it online. If Hummingbird High lives on, it won’t be because of any strategy or grand plan. It’ll be because I still have an insatiable sweet tooth, and I still genuinely care about eating good dessert.

That’s probably enough for right now.

photo of rectangular cookie cake sliced into squares

I recommend the following ingredients for this 9 x 13 inch cookie cake recipe:

  • Brown Sugar. During my recipe tests, I found that either light or dark brown sugar works in the recipe. I prefer dark brown sugar since I think that cookie cake a subtle caramel flavor—but really, either will do just fine!

  • Kosher Salt. I think that kosher salt is the best salt for baking recipes. But you can replace the kosher salt in the recipe with table salt. Just use half the amount listed in the recipe when you do!

  • Chocolate Chips. Although I typically recommend using chopped chocolate or chocolate feves in my chocolate chip cookie recipes, I recommend using classic chocolate chips in this cookie cake. My recipe taste testers preferred their nostalgic, classic flavor in this cookie cake recipe. And don’t forget to grab my recommendations in The Best Chocolate For Chocolate Chip Cookies.

  • Whole Milk. I recommend using whole milk for the best tasting frosting. Skim and low-fat milk won’t taste as creamy. You can also use plant-based milk like almond, coconut, soy, or oat. Just note that they might make the frosting taste like them, too.
photo of Michelle from Hummingbird High holding up slices of cookie cake placed on white plates
photo of michelle from hummingbird high greasing the sheet pan for the cookie cake
To make the cake, start by generously buttering the bottom and sides of a 9 x 13-inch sheet pan with around 1 Tablespoon of butter.
photo of the cookie dough for the cookie cake in a bowl
This is what the chocolate chip cookie dough looks like after bringing it together—pretty standard! At this point, you’re ready to press it into the sheet pan.
photo of michelle from hummingbird high pressing the cookie dough onto the pan with her hands
Don’t dump the cookie dough all at once into the center of the pan! Instead, transfer the dough bit by bit, pressing it into the pan as you go until it forms an even layer.
photo of michelle from hummingbird high showing the cookie dough in the sheet pan ready for baking
If you don’t want to leave finger marks on the dough, you can use a stiff rubber spatula or offset spatula to smoothen it out before baking.
photo of michelle from hummingbird high scattering chocolate chips over the cookie dough
I like to reserve ¼ cup of the chocolate chips to scatter over the dough before baking.
photo of the cookie dough pressed into the pan ready to be baked
The chocolate chips on top of the cake ensure every slice looks bakery-perfect and gives the cake extra texture.
photo of the baked cookie cake before it's been decorated
Here’s what it looks like after it’s baked. Make sure to cool the cake completely before frosting (or the frosting will melt).
photo of michelle from hummingbird high piping frosting onto the cookie cake
To pipe the border, I used two star tips. I piped one big star on the cookie cake, then another star on top of it to give it a layered look.
photo of michelle from hummingbird high sprinkling sprinkles onto the cookie cake frosting
I also recommend decorating the frosting with sprinkles for a festive, bakery-style look!

My Best Recipe Tips To Help You Make The Cake

You Need Both Salted and Unsalted Butter

Note that while the chocolate chip cookie cake dough instructs you to use salted butter, you’ll need to use UNSALTED butter for the frosting. In general, it’s not a good idea to use salted butter for frosting. Frosting recipes usually require a LOT of butter. Using salted butter at that volume will definitely make your frosting taste salty.

In a pinch, if you only have unsalted butter on hand, don’t worry! Simply follow the recipe. There’s no need to increase the amount of salt in the cookie dough. If you only have salted butter on hand, feel free to use it in the frosting recipe. But don’t say I didn’t warn you if you find it to be too salty and weird! You may also want to skip the “pinch of salt” I instruct you to use.

  • To save myself some clean up, I melt the butter in the bowl I’m planning to make the cookie dough in. Specifically: I use a small bowl to mix the dry ingredients. Then, I use the microwave to melt the butter in a medium bowl big enough to mix the dough in, add the sugars, egg, and extract, then the dry ingredients and chocolate. As a result, I only need two bowls when making the cookie dough!

  • When prepping ingredients, I also melt the butter first. That way, it has time to cool while I prep the rest of the ingredients. Doing so ensures your butter isn’t too hot and won’t scramble the egg when you add it to the dough!

  • Be mindful when melting the butter for these cookies! You don’t want the butter to sizzle, crackle, or pop. I like to chop it up into 1-inch cubes then melt it in a small sauce pot over medium-low heat. Be sure to stir the butter constantly as it melts to help prevent it from overheating.
photo of rectangular cookie cake frosted and decorated with "OMG YAY"
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Get the Recipe: Rectangular 9 x 13 Inch Cookie Cake

Prep: 10 minutes
Cook: 20 minutes
Bake Time: 14 minutes
Total: 44 minutes
Servings: 1 (9 x 13-inch) cake
Author: Michelle Lopez
This Rectangular 9 x 13 Inch Cookie Cake is a quick and easy dessert based on my popular Weeknight Baking cookie recipe. The dough comes together in just 5 minutes—no mixer or chilling required! Baked in a quarter sheet pan and topped with creamy American buttercream frosting, it’s soft, chewy, and filled with melty chocolate chips. A nostalgic, crowd-pleasing treat that tastes just like a classic mall cookie cake!
(5 stars) 3 reviews
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Ingredients

For the Chocolate Chip Cake

  • 1 ⅔ cup (7.5 ounces or 213 grams) all-purpose flour
  • ½ teaspoon baking powder
  • ½ teaspoon baking soda
  • 1 teaspoon kosher salt
  • ½ cup (4 ounces or 113 grams) salted (preferred) OR unsalted butter, melted and cooled slightly, plus more for pan
  • ¾ cup tightly packed (5.65 ounces or 160 grams) dark OR light brown sugar
  • ¼ cup (1.75 ounces or 50 grams) granulated sugar
  • 1 large egg
  • 2 teaspoons pure vanilla extract
  • 1 ¼ cups (8 ounces or 227 grams) semisweet chocolate chips

For the American Buttercream Frosting

  • ½ cup (1 stick or 4 ounces or 113 grams) unsalted butter, at room temperature
  • 2 cups (8 ounces or 227 grams) confectioners' sugar, sifted
  • 1 Tablespoon whole milk
  • ½ teaspoon pure vanilla extract
  • pinch kosher salt
  • food coloring

Equipment

  • 9 x 13-inch sheet pan

Instructions
 

For The Chocolate Chip Cookie Cake

  • Prep the oven and pan. Position a rack in the center of the oven and preheat the oven to 350°F.
    Generously butter the bottom and sides of a 9 x 13-inch sheet sheet pan.
  • Mix the dry ingredients. In a small bowl, whisk together the flour, baking soda, baking powder, and kosher salt.
  • Mix the butter, sugars, egg, and extract. In a medium bowl, use a rubber spatula to mix together the butter and sugars until moistened, about 1 minute.
    Add the egg and vanilla extract and mix until combined.
  • Add the dry ingredients and chocolate. Gradually mix in the dry ingredients until just combined.
    Add the chocolate all at once and mix until the chocolate is evenly distributed throughout, about 1 minute.
  • Assemble the cookie dough in the pan. Transfer the cookie dough into the prepared skillet by scraping a small portion of the dough into the pan and using a wooden spoon, stiff rubber spatula, or your hands to press the dough down into the sheet pan. Press the dough evenly over the bottom of the pan.
  • Bake the cookie cake. Bake the chocolate chip cookie cake for 14 to 16 minutes, or until the edges are set but the center is still gooey.
    Cool on a wire rack completely before frosting. The cookie cake can be stored by slicing it into squares after frosting. Store the wedges in an airtight container at room temperature for up to 3 days.

For the American Buttercream Frosting

  • Make the icing. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium-low until smooth and creamy, about 1 minute.
    Reduce the mixer to low and add the confectioners' sugar ½ cup at a time, beating until combined. Scrape down the bottom and sides of the bowl with a rubber spatula.
    Add the milk, vanilla, salt and food coloring all at once and beat on low just to incorporate the liquid. Scrape down the bottom and sides of the bowl once more, then beat on medium-high until the frosting is creamy and smooth, 2 to 3 minutes.

Notes

Can you freeze the unbaked chocolate chip cookie cake?

Yes, you can! To freeze the unbaked cookie dough, follow the recipe to make the dough as instructed. Instead of pressing the cookie dough into the pan, mold it into a rough ball and press down to make a disc. Cover tightly with plastic wrap and freeze for up to 3 months. To bake into a cookie cake, thaw the disc overnight in the refrigerator and follow the instructions in the recipe to press it into the pan and bake.
Did you make this recipe?Please leave a star rating and review in the form below. I appreciate your feedback, and it helps others, too!
Michelle holding Weeknight Baking cookbook covering her face.

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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.

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