Skip the store-bought birthday cake and make this sheet pan chocolate birthday cake instead! My homemade version consists of two layers of rich chocolate sponge decorated with a silky chocolate Swiss meringue buttercream and topped with chocolate ganache. Its rectangular shape makes it easier to decorate, transport, and cut slices for a crowd!
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Why you'll love this chocolate birthday cake
- Fudgy, Moist Texture: Unlike most chocolate cake recipes, this recipe bakes up incredibly fudgy & moist with a pronounced chocolate flavor, an even, tight crumb, and a melt-in-your-mouth texture that is utterly irresistible.
- Silky, Smooth Buttercream: This Swiss meringue buttercream is silky yet sturdy, making it perfect for holding up cake layers and piping into designs.
- Easily Sharable: In sheet cake form, this cake is the perfect dessert for a crowd–especially for birthdays!
For more birthday recipes, try my Yellow Cake with Chocolate Frosting, Birthday Cake Sugar Cookies, Small Vanilla Cake Recipe, and Brown Butter Chocolate Chip Cookie Cake.
Ingredient Notes
- Flour: Use high-quality unbleached all-purpose flour.
- Cocoa Powders: Use a combination of dutch process and black cocoa powders for an extra rich flavor. Alternatively, you can use unsweetened cocoa powder, but it will not be quite as rich.
- Leavener: Baking powder is all you need to give this cake the perfect rise and texture.
- Oil: Use a neutral oil such as light-tasting extra virgin olive oil.
- Coffee: Add freshly brewed hot coffee at the end to "bloom" the cocoa powders in the cake.
- Chocolate: Use your favorite dark chocolate chips, chunks, or bars!
- Butter: Use high quality European-style butter for best overall flavor.
See recipe card for full information on ingredients and individual quantities.
Step by Step Instructions
Here are step by step photos and instructions on how to make this chocolate birthday cake recipe! For the full ingredient list and method, see the recipe card at the end of this post.
Make the cake batter
In a medium bowl, whisk together the flour, sugar, cocoa powders, baking powder, and salt. In a large bowl, whisk together the milk, oil, eggs, and vanilla. Add the dry ingredients to the wet and whisk until just combined. Lastly, whisk in the hot coffee until fully combined.
Bake
Pour half of the cake batter into the prepared pan (or divide between two 9x13 pans) and wrap the soaked cake strips around the outside of the pan. Weigh the batter for even cake layers. Bake for about 20-25 minutes or until a toothpick inserted comes out clean the cake pulls away from the sides of the pan.
Make the buttercream
Make the meringue base and mix on low speed until it cools down to at least 85 degrees F. Cut the butter into cubes and add to the meringue a few pieces at a time, allowing them to fully incorporate before adding more. Once the buttercream has mostly come together, change the whisk attachment to the paddle and keep mixing on low speed until homogenous and smooth. Lastly, mix in the melted chocolate on low speed until fully combined.
Decorate
Place the first cake layer on a serving tray (I used an upside down baking sheet). Add eight 3 tablespoon scoops of buttercream and spread into an even layer. Place the second cake layer on top and repeat. Spread an even layer of buttercream on the sides (crumb coat), then chill in the fridge for at least 10 minutes. Remove the cake from the fridge and apply a thicker layer of buttercream to the sides. Pipe buttercream along the edges of the cake as desired, then place in the fridge or freezer while you make the ganache.
Top with ganache and serve
In a small saucepan, place the heavy cream over low-medium heat. Stir frequently with a rubber spatula, and bring to simmer, or about 190 degrees F. Remove the pan from heat and add the chocolate and butter, and gently stir with a rubber spatula until fully combined. Immediately pour the warm ganache onto the cake and spread into an even layer. Allow to set at room temperature or in the fridge before slicing.
Expert Baking Tips
- Bake half the batter or use two pans. If you have two 9x13 cake pans, you can divide the batter between them and bake. If not, simply pour half the batter into your pan (weigh it for best results), bake, and repeat with the remaining batter. Be sure to let the pan cool before baking the second layer!
- Black cocoa powder substitute: If you do not have black cocoa powder, you can use an equal amount of dutch process cocoa powder, making it a total of 84g or 1 cup.
- Use cake strips to create flat cake layers. Soak these wilton cake strips in ice water before starting the cake batter. Just before baking, wrap the cake strips around the pan. The cold temperature on the outside of the cake will prevent the edges from baking faster than the center, resulting in an evenly baked flat cake.
- Wait until meringue cools down before adding butter. It is SO important to wait until the meringue drops down to at least 85 degrees F or you will risk the butter melting and the whole thing turning into a big soupy mess.
Recipe FAQs
Dutch process cocoa powder is THE best cocoa powder for baking. Because it's neutralized with an alkalizing agent, it has a smoother flavor and creates the most fudgy and chocolatey baked goods! Black cocoa powder is similar to dutch process, but richer in flavor and darker in color. It is typically used in small amounts alongside another cocoa powder to enhance the color and flavor of the baked good. It smells like actual chocolate cake and is just magical to bake with!
Cakes may dome in the middle when they bake because the outside bakes faster than the center, so the center has more time to rise. This is not ideal for layer cakes, because it is a pain to have to trim away the top of the cake. The best way to ensure your cake layers bake up flat rather than doming is to use cake strips. Soak the cake strips in cold water before wrapping around the outside of the cake pan. This will ensure that the outside of the cake does not bake faster than the center, resulting in an evenly baked, flat cake.
Be wary of over-heating or over-mixing or the ganache might split. When ganache splits, the fat solids separate and it appears grainy. If this happens, sometimes it can be fixed by adding a splash of cold heavy cream or small amount of butter.Â
Store this chocolate birthday cake in an airtight container at room temperature for 3-5 days, or individual slices wrapped in plastic wrap in the freezer for up to 3 months. Â
Baking in Grams
All of the recipes on this blog are carefully developed with gram measurements so you can easily recreate them in your own kitchen with success. Volume measurements are extremely inaccurate and leave room for significant errors. Not all measuring cups are made equally, so your one cup of flour will be different from my one cup of flour. By providing precise measurements in grams (aside from minor ingredients, which are given in tsp/tbsp), you can make these recipes accurately and with less cleanup! All you need is this kitchen scale.Â
If this still isn't enough to convince you, I have provided volume measurements in the recipe card. If you are interested in understanding the conversions, this is the best conversion chart.
But trust me, once you try baking in grams you'll never turn back!
Happy baking! x
Other birthday recipes to try
If you tried this recipe, I'd love to know how it turned out for you! Leave a star rating & review below and post a picture (or video!) on Instagram and tag me so I can see your bakes! Not ready to make this recipe yet? Click the heart button on the right of your screen to save it for later 🙂
📖 Recipe
Sheet Pan Chocolate Birthday Cake
Equipment
Ingredients
For the cake layers:
- 320 g (2 â…” cups) all-purpose flour
- 450 g (2 ½ cups) granulated sugar
- 63 g (¾ cup) Dutch process cocoa powder
- 21 g (¼ cup) black cocoa powder
- 2 teaspoon baking powder
- 1 teaspoon kosher salt
- 300 g (1 â…“ cup) whole milk, room temp
- 200 g (1 cup) neutral oil
- 3 eggs, room temp
- 1 tablespoon vanilla extract
- 150 g (¾ cup) freshly brewed coffee,
For the chocolate Swiss meringue buttercream:
- 210 g (about 6) egg whites
- 450 g (2 ¼ cups) granulated sugar
- 510 g (2 ¼ blocks) salted butter, room temp, but on the cooler side
- 170 g (1 cup) semisweet chocolate, melted
For the chocolate ganache:
- 170 g (¾ cup) heavy cream
- 113 g (4 oz) semisweet chocolate
- 28 g (2 tablespoon) unsalted butter, room temp
Instructions
For the cake layers:
- Preheat the oven to 350 degrees F. Grease and line one 9x13 cake pan with parchment paper.
- Soak cake strips in ice cold water.
- In a medium bowl, whisk together the flour, sugar, cocoa powders, baking powder, and salt. Set aside.
- In a large bowl, whisk together the milk, oil, eggs, and vanilla.
- Add the dry ingredients to the wet and whisk until just combined.
- Lastly, whisk in the hot coffee until fully combined.
- Pour half of the cake batter into the prepared pan (or divide between two 9x13 pans) and wrap the soaked cake strips around the outside of the pan. Weigh the batter for even cake layers.
- Bake for about 20-25 minutes or until a toothpick inserted comes out clean the cake pulls away from the sides of the pan.
- Turn the cake out onto a wire rack to cool completely. Repeat with the remaining half of the cake batter.
- Wrap the cake layers with plastic wrap and set aside until ready to assemble.
For the chocolate Swiss meringue buttercream:
- Wipe the bowl of a stand mixer and whisk attachment down with white vinegar.
- Add the egg whites and sugar to the bowl and whisk until fully combined.
- Place over a small saucepan of simmering water, and whisk frequently until it reaches 160 degrees F or until the sugar is completely dissolved and the mixture no longer feels grainy.
- Move the bowl over to the stand mixer with the whisk attachment. Whisk on medium-high speed until medium peaks form.
- Add the vanilla and continue whisking until stiff peaks form.
- Turn the mixer down to low speed, and wait until the meringue cools down to at least 85 degrees F.
- Cut the butter into cubes and add to the meringue a few pieces at a time, allowing them to fully incorporate before adding more.
- Once all of the butter is added, it may look curdled, but keep beating for a few more minutes and it will come together.
- Once the buttercream has mostly come together, change the whisk attachment to the paddle and keep mixing on low speed until homogenous and smooth.
- Lastly, mix in the melted chocolate on low speed until fully combined.
For assembly:
- Place the first cake layer on a serving tray (I used an upside down baking sheet). Add eight 3 tablespoon scoops of buttercream and spread into an even layer. Place the second cake layer on top and repeat.
- Spread an even layer of buttercream on the sides (crumb coat), then chill in the fridge for at least 10 minutes.
- Remove the cake from the fridge and apply a thicker layer of buttercream to the sides.
- Pipe buttercream along the edges of the cake as desired, then place in the fridge or freezer while you make the ganache.
For the ganache:
- In a small saucepan, place the heavy cream over low-medium heat. Stir frequently with a rubber spatula, and bring to simmer, or about 190 degrees F.
- Remove the pan from heat and add the chocolate and butter, and gently stir with a rubber spatula until fully combined.
- Immediately pour the warm ganache onto the cake and spread into an even layer. Allow to set at room temperature or in the fridge before slicing.
Notes
- Bake half the batter or use two pans. If you have two 9x13 cake pans, you can divide the batter between them and bake. If not, simply pour half the batter into your pan (weigh it for best results), bake, and repeat with the remaining batter. Be sure to let the pan cool before baking the second layer!
- Black cocoa powder substitute:Â If you do not have black cocoa powder, you can use an equal amount of dutch process cocoa powder, making it a total of 84g or 1 cup.
- Use cake strips to create flat cake layers. Soak these wilton cake strips in ice water before starting the cake batter. Just before baking, wrap the cake strips around the pan. The cold temperature on the outside of the cake will prevent the edges from baking faster than the center, resulting in an evenly baked flat cake.
- Wait until meringue cools down before adding butter. It is SO important to wait until the meringue drops down to at least 85 degrees F or you will risk the butter melting and the whole thing turning into a big soupy mess.
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