This decadent chocolate brownie cake recipe combines two of my favorite desserts for the ultimate sweet treat. I baked up a rich, dense, brownie-like chocolate cake and layered it with semisweet chocolate buttercream. This cake has a super fudgy texture just like a brownie and makes a great birthday cake for any chocolate lover.
This brownie cake recipe is a fusion of fudgy brownies and chocolate cake. I made it with cocoa powder and melted chocolate for a super fudgy flavor and topped it with the richest chocolate frosting you’ll ever taste. This one takes a little bit to make, but trust me, it’s worth the effort!
What’s in This Brownie Cake Recipe?
- Flour: All-purpose flour gives the cake structure.
- Cocoa Powder: Creates a deep base of chocolate flavor in the cake. While you can use any unsweetened cocoa powder you prefer, I like to use natural cocoa powder here because the baking soda helps to neutralize the acidity of natural cocoa powder, letting its rich flavor shine.
- Leavening: Baking powder and baking soda work together to help the cake rise.
- Butter: Unsalted butter enriches and tenderizes the cake as well as forms the creamy base of the frosting.
- Sugar: A combination of brown and granulated sugar sweetens and deepens the flavor of the cake, while powdered sugar sweetens and thickens the frosting.
- Eggs: Bind the cake and help keep it moist.
- Vanilla Extract: Enhances the overall flavor of both the cake and the frosting.
- Buttermilk: Makes the cake super moist and tender.
- Semisweet Baker’s Chocolate: Adds rich chocolate flavor to the cake and the frosting.
Note: This recipe is one of those few exceptions on our site that has more than 10 ingredients. We try to keep things VERY easy around here, and limiting ingredients and time spent is one of our favorite ways. That being said, this recipe is too delicious to leave out of our recipe box! It’s an exception that is so flavorful and worth the extra ingredients if you have the time and resources to make it.
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How to Store
Store leftover brownie cake in an airtight container at room temperature for up to 3 days or tightly wrapped in plastic wrap in the refrigerator for up to 5 days or in the freezer for up to 1 month. Let thaw overnight in the refrigerator before enjoying at room temperature.
Tips for Success
- Measure your flour and cocoa powder with a food scale to ensure you use the correct amount. Otherwise, your cake will come out dry and crumbly. You can also spoon the flour into a measuring cup instead of scooping with the measuring cup for better accuracy.
- It’s very important to use room-temperature ingredients to help all the ingredients mix together better. This will allow your cake to bake more evenly and come out light and fluffy.
- Do not overmix the cake batter; otherwise, your cakes will come out tough.
- Because brownie cake is supposed to be extra moist, it can be tough to tell when the cake is done baking. If using the toothpick test, the toothpick should come out with sticky but thick, nearly dry batter. If the batter is thin and glossy, it needs more time to bake.
- Chilling the cake in the fridge for at least an hour is an important step so the cake firms up a bit before frosting or cutting to flatten the tops. If the frosting is too thick to smooth onto the cake, beat in 1 tablespoon of heavy cream.
Brownie Cake Recipe
Ingredients
For the Cake
- 3¼ cups all-purpose flour
- 1 cup unsweetened cocoa powder
- 2 teaspoons baking powder
- 1 teaspoon baking soda
- 1½ cups unsalted butter slightly melted (3 sticks)
- 1½ cups brown sugar
- ¾ cup granulated sugar
- 4 large eggs room temperature
- 1 tablespoon pure vanilla extract
- ½ cup buttermilk room temperature
- 12 ounces semisweet Baker’s chocolate melted and cooled (3 bars)
For the Frosting
- 5 cups powdered sugar
- 1½ cup unsalted butter slightly melted (3 sticks)
- 6 ounces semisweet Baker’s chocolate melted and cooled (1½ bars)
- 2 teaspoons pure vanilla extract
- Brown gel food coloring optional, to boost color
Optional Toppings
- 4 ounces Baker’s semisweet chocolate melted
- Brownies cut into bite-sized pieces
- Chocolate sprinkles
Equipment
- Kitchen Scale (optional)
- 3 8-inch Round Cake Pan
- Stand Mixer
- Piping Tip Set
Instructions
For the Cake
- Preheat oven to 350°F. Spray three 8-inch round cake pans with nonstick spray and line the inside bottom of each pan with parchment paper (the parchment paper will help the cakes slide easily out of the pan once baked and cooled). Set pans aside for now.
- In a medium bowl, stir the flour, cocoa powder, baking powder, and baking soda together. Set aside.3¼ cups all-purpose flour, 1 cup unsweetened cocoa powder, 2 teaspoons baking powder, 1 teaspoon baking soda
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, brown sugar, and granulated sugar on high until mixed well, about 2 minutes.1½ cups unsalted butter, 1½ cups brown sugar, ¾ cup granulated sugar
- Beat the eggs and vanilla extract into the butter mixture until well combined.4 large eggs, 1 tablespoon pure vanilla extract
- Beat half of the flour mixture into the wet ingredients. Beat this on low speed just until combined. Do not overmix.
- Beat in all of the buttermilk just until combined. Again, don’t overmix.½ cup buttermilk
- On low speed, beat in the remaining flour mixture just until combined.
- Stir in the melted chocolate by hand until well mixed. Do not use the electric beaters for this step.12 ounces semisweet Baker’s chocolate
- Divide the cake batter evenly between the 3 prepared cake pans (about 672 grams per pan). Try to get the same amount in each pan so that they bake at the same speed.
- Bake in oven for 30 minutes or until toothpick inserted in middle of each comes out clean or with moist crumbs.
- Remove cakes from oven and let cakes cool in pans for 15 minutes. After 15 minutes, remove cakes from pans and let cool completely on a wire rack.
- Once cakes have completely cooled to room temperature, wrap each cake individually in food-safe plastic wrap and place cakes in fridge for at least 1 hour. Chilling the cakes in the fridge before frosting will help them hold their shape and not crumble during decorating.
- Removed chilled cakes from the fridge and use a large serrated knife to cut any dome tops off cakes so they have flat tops. These cakes bake up pretty flat (like brownies) so there won’t be a lot to cut off the tops.
For the Frosting
- In the bowl of a stand mixer fitted with the whisk attachment, beat the powdered sugar, butter, melted chocolate, and vanilla extract together on high speed until light and fluffy, about 5 minutes. Add a few drops of brown food coloring to deepen the color, if desired.5 cups powdered sugar, 1½ cup unsalted butter, 6 ounces semisweet Baker’s chocolate, 2 teaspoons pure vanilla extract, Brown gel food coloring
- Place a thin layer of frosting (about 2 tablespoons) in the middle of a cake board or cake plate then place one cake (cut side facing up) on top of that frosting. This helps secure the cake to the cake board or plate so it doesn’t slide off during decorating.
- Add a generous layer of frosting on top of that first layer of cake and use an angled cake spatula to smooth that frosting into an even layer.
- Add the second layer of cake (cut side up) over that frosting then add another generous layer of frosting on top and smooth it out using the angled cake spatula.
- Add the third and final layer of cake with the bottom side facing up. You’ll now have a 3-layer cake.
- Frost a thin layer of frosting around the top and sides of cake. This first coating of frosting (called a crumb coat) is meant to secure all the crumbs to the cake. To get the layers of frosting smooth, use a tool like a cake scraper to smooth the icing out.
- Place the lightly frosted cake into the freezer for 10 minutes so the crumb coat hardens up a bit before frosting the next layer.
- Remove cake from freezer and smooth on a second layer of frosting around the top and sides of the cake. Use the cake scraper to smooth this out.
- Using a Wilton 1M icing tip and an icing bag, frost swirls along the top border of the cake.
- Optional: add 4 ounces of melted chocolate to the top of the cake and top with cut brownie pieces. The melted chocolate is used to secure the brownie pieces to the cake.4 ounces Baker’s semisweet chocolate, Brownies
- Optional: add chocolate sprinkles to the bottom border of the cake.Chocolate sprinkles
Notes
- Nutritional information does not include optional ingredients.
How to Make Brownie Cake Step-by-Step
Prep the Wet and Dry: Preheat your oven to 350°F, spray three (8-inch) round cake pans with nonstick spray, and line the inside bottom of each pan with parchment paper. Set pans aside for now. In a medium bowl, stir 3¼ cups of all-purpose flour, 1 cup of unsweetened cocoa powder, 2 teaspoons of baking powder, and 1 teaspoon of baking soda together. Set aside. In the bowl of a stand mixer fitted with the paddle attachment, beat 1½ cups of unsalted butter, 1½ cups of brown sugar, and ¾ cup of granulated sugar on high until mixed well, about 2 minutes.
Beat in the Eggs: Beat 4 large eggs and 1 tablespoon of vanilla extract into the butter mixture until well combined. Beat half of the flour mixture into the wet ingredients. Beat this on low speed just until combined. Do not overmix.
Add the Buttermilk: Beat in ½ cup of buttermilk just until combined. Again, don’t overmix. On low speed, beat in the remaining flour mixture just until combined.
Fold in the Chocolate: Stir in 12 ounces of melted semisweet Baker’s chocolate by hand until well mixed. Do not use the electric beaters for this step. Divide the cake batter evenly between the 3 prepared cake pans (about 672 grams per pan).
Bake and Chil the Cakes: Bake in the oven for 30 minutes or until a toothpick inserted in the middle of each comes out clean or with moist crumbs. Remove cakes from oven and let cakes cool in pans for 15 minutes. After 15 minutes, remove cakes from pans and let cool completely on a wire rack. Once cakes have completely cooled to room temperature, wrap each cake individually in food-safe plastic wrap and place cakes in fridge for at least 1 hour.
Make the Frosting: Remove the chilled cakes from the fridge and use a large serrated knife to cut any dome tops off cakes so they have flat tops. In the bowl of a stand mixer fitted with the whisk attachment, beat 5 cups of powdered sugar, 1½ cups of unsalted butter, 6 ounces of melted semisweet Baker’s chocolate, and 2 teaspoons of vanilla extract together on high speed until light and fluffy, about 5 minutes. Add a few drops of brown gel food coloring to deepen the color, if desired.
Crumb-Coat the Cake: Place a thin layer of frosting (about 2 tablespoons) in the middle of a cake board or cake plate then place one cake (cut side facing up) on top of that frosting. Add a generous layer of frosting on top of that first layer of cake and use an angled cake spatula to smooth that frosting into an even layer. Add the second layer of cake (cut side up) over that frosting then add another generous layer of frosting on top and smooth it out using the angled cake spatula. Add the third and final layer of cake with the bottom side facing up. You’ll now have a 3-layer cake. Frost a thin layer of frosting around the top and sides of cake. To get the layers of frosting smooth, use a tool like a cake scraper to smooth the icing out. Place the lightly frosted cake into the freezer for 10 minutes so the crumb coat hardens up a bit before frosting the next layer.
Decorate the Cake: Remove the cake from the freezer and smooth on a second layer of frosting around the top and sides of the cake. Use the cake scraper to smooth this out. Using a Wilton 1M icing tip and an icing bag, frost swirls along the top border of the cake. For decoration, optionally add 4 ounces of melted Baker’s semisweet chocolate to the top of the cake and top with cut brownie pieces. You can also add chocolate sprinkles to the bottom border of the cake.
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