Brownie Cake

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This easy brownie cake is for all of the brownie lovers out there! It has all of the wonderful flavor of brownies in the form of a two layer cake.

Brownie Cake, sliced, on a cake pedestal.

This cake is made from a doctored brownie mix, which is why it has the flavor and texture of a cake-like brownies. It has delicious chocolate brownie flavor without being overly rich.

At two layers, it doesn't stand quite as tall as our usual cakes (approximately an inch shorter), but is every bit as impressive!

Keep this brownie cake in mind the next time you need a great birthday cake recipe, potluck dessert, holiday cake, and more!

Ingredients for Brownie Cake

Here is a quick look at the star players in today's easy brownie cake recipe:

Ingredients for Brownie Cake.

Duncan Hines Double Fudge Brownie Mix- This has been our favorite brownie mix to use with this recipe so far, but we have only tested one other. (We discuss this more in the notes). It comes with a packet of fudge syrup which we used in the batter as well!

Sour Cream Just as with doctored cake mix recipes like our Orange Spice Cake and Chocolate Mousse Cake recipes, sour cream adds richness, improves the texture, and helps to extend the recipe further.

Flour and Sugar: These ingredients help to extend the recipe further, and also give the brownie layers a more "cake like" quality.

Baking Powder: We added a teaspoon of powder to the brownie batter to give it a bit more rise.

How to Make a Brownie Cake

  • Grease two 8 inch cake layers. We also added circles of parchment to the bottom of each pan (as usual).
  • This recipe can be prepared in a large mixing bowl, just as when making brownies. No electric mixer is needed.
  • Combine dry ingredients in large bowl and whisk together. (This is the brownie mix, flour, sugar, cocoa powder, and baking powder.)
Brownie Cake Recipe dry ingredients in bowl.
  • Add the remaining ingredients (eggs, sour cream, fudge packet (if your mix has one), water, and vegetable oil) and stir until well combined. I prefer to use a rubber spatula for this step.
Ingredients for the Brownie Cake Recipe in a mixing bowl.
  • This recipe makes 5 cups of batter, enough for two 8 inch cake layers. Divide the cake batter between two 8 inch round cake pans and place in the oven.
  • Bake at 350 for 25-30 minutes, or until a toothpick can be inserted and comes out clean or with just a few crumbs attached.
Two freshly baked brownie cake layers in pans on a wire rack.

Cool the layers on a wire rack for 5 minutes before turning out. Make sure to cool them completely before frosting.

Chocolate Buttercream Frosting

There are many frostings and fillings that would pair well with this chocolate brownie cake recipe!

Today, we opted for Chocolate Buttercream. This delicious recipe is so simple to make. It is a combination of softened butter, confectioners sugar, unsweetened cocoa powder, milk, vanilla extract, and a pinch of salt.

If the frosting is too thick, add a bit more milk. If it is too thin, add a bit more confectioners sugar.

Other great fillings and frostings for this brownie cake are: Whipped Cream filling, easy Chocolate Mousse filling, Chocolate Cream Cheese Frosting, and Peanut Butter Buttercream just to name a few.

Chocolate Buttercream Frosting in mixing bowl.

Assembling the Brownie Cake

Once the brownie cake layers have completely cooled, place the first layer on a cake base or pedestal. Spread with a layer of chocolate frosting.

Frosting a layer of chocolate buttercream onto chocolate cake layer.

Top with the next brownie cake layer. Apply a thin layer of frosting on top and around the sides of the cake. (This is the crumb coat.)

At this point, we like to chill the cake for 15 minutes in the freezer to firm everything up (or longer in the refrigerator). Then, apply the second layer of chocolate frosting.

Decorating the Brownie Cake

Decorate however you like! I used a small offset spatula to add texture around the sides of the cake by creating simple diagonal strokes.

Adding texture to the frosted cake with an offset spatula.

For the top of the cake, I added rows of buttercream shells and then piped a buttercream rosette in the center.

Piping chocolate buttercream shells on top of the frosted brownie cake with a 1M piping tip.

All of this was done with a large star (1M) piping tip. (Find more details in our video on the basics of star tip piping!)

Top view of the decorated brownie cake. Lots of buttercream shell piping.

Here is a peek at the inside of the cake!

Sliced Brownie Cake on a white cake pedestal.

Recipe FAQs

This cake is chocolatey, moist, and tastes like a brownie! However, I would not describe it as fudgy or rich.

We used Duncan Hines Double Fudge Brownie Mix and have also experimented with Ghirardelli Double Chocolate Box Mix. Both worked, but our favorite was Duncan Hines as the cake layers tasted more like brownies.

We will update if we experiment with different mixes!

Yes, just as with the majority of our cakes from our lemon cake recipe to pound cake recipe, strawberry cake recipe, and more, these layers freeze beautifully.

To freeze, wrap the brownie cake layers individually once they have cooled down to slightly warm or room temperature. Wrap in plastic wrap followed by foil.

For additional support, we often place the cake layers on foil-wrapped cake boards before wrapping. The wrapped cake layers can be frozen for up to three months!

To thaw: Move the wrapped cake layers from the freezer to the kitchen counter and unwrap after 30-45 minutes. Allow to warm to desired amount for assembly.

We have some great chocolate cake mix recipes on our site, including our easy Chocolate Mousse Cake, German Chocolate Cake Mix recipe, and more.

The texture of the doctored cake mix recipes are softer and fluffier than the brownie cake.

Today's brownie cake recipe is slightly denser than our other chocolate cake mix recipes and has a distinctive "brownie flavor". If you love brownies, you'll love this cake.

We hope that you enjoy this Brownie Cake! Don't miss our full collection of favorite Cake Recipes, including more cake mix recipes as well as cake recipes from scratch.

More Chocolate Cakes

If you love chocolate cakes, we have so many to share with you!

Some of our most popular are our Chocolate Cake from Scratch, Easy Marble Cake, Chocolate Truffle Cake, and German Chocolate Cake.

Brownie Cake, sliced, on a cake pedestal.

Brownie Cake

This easy Brownie Cake Recipe has all of the wonderful flavor of cake-like brownies in the form of a layer cake! It starts with a box of brownie mix, and we've frosted it with homemade chocolate buttercream.
Prep Time: 15 minutes
Cook Time: 30 minutes
Course: Dessert
Servings: 15
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Ingredients

  • 1 Box Brownie Mix (We like Duncan Hines Double Fudge Brownie Mix- 17.6 oz) *See Notes
  • ½ cup (60g) All Purpose Flour
  • ½ cup (100g) granulated sugar
  • 1 teaspoon (4g) Baking Powder
  • Tablespoons (15g) Unsweetened Cocoa Powder
  • ½ cup (108g) vegetable oil
  • 1 cup sour cream (we use full fat)
  • ½ cup water
  • 3 large eggs
  • Fudge Packet (if your brownie mix comes with one)

For the Chocolate Buttercream

  • 2 sticks (226g) unsalted butter, softened (Do not microwave)
  • 6 cups (690g) powdered sugar
  • ¾ cup (70g) unsweetened cocoa (measure then sift)
  • ⅓ -½ cup (72g) milk (adjust amount for desired consistency)
  • 2 teaspoons 8g vanilla extract 8 grams
  • ½ teaspoon 3g salt

Instructions

  • Preheat oven to 350℉. Grease two 8 inch round cake pans. We also added circles of parchment to the bottom of each pan (as usual).
  • This recipe can be prepared in a large mixing bowl, just as when making brownies from a mix. No mixer needed.
  • Combine dry ingredients in large bowl and whisk together until combined. (This is the brownie mix, flour, sugar, cocoa powder, and baking powder.)
  • Add the remaining ingredients (eggs, sour cream, fudge packet (if your mix has one), water, and vegetable oil) and stir until well combined. I find it easiest to use a rubber spatula for this step.
  • Divide the cake batter between two 8 inch cake pans. (This recipe makes about 5 cups of batter.)
  • Bake at 350℉ for 25-30 minutes or until a toothpick can be inserted into the cake layers and comes out clean or with just a few crumbs attached.
  • Cool the cake layers in the cake pans (preferably on a cooling rack) for 5 minutes before turning out. Cool completely before frosting.

For the Chocolate Buttercream

  • Add butter and mix on low to medium speed until smooth. Add vanilla and blend into the butter.
  • Add powdered sugar, salt, and cocoa powder.
  • Add most of the milk and mix on low speed, increasing to medium as the ingredients become incorporated.
  • Continue to mix adding remaining milk as needed. It may take 3-5 minutes to reach the smoothness and consistency you like. It will take longer if using a hand mixer. As you mix, the frosting will become very smooth. You can add additional milk (1 Tablespoon at a time) if the frosting is too thick or additional powdered sugar if too soft.

Decorating the Cake

  • Place the first cake layer on a cake pedestal and spread with frosting. Top with the second cake layer and frost the cake around the sides and top with a thin layer of frosting. (This is the "crumb coat".)
  • At this point, we like to chill the cake in the freezer for 15 minutes (or longer in the refrigerator) to firm everything up. (Chill the bowl of frosting in the refrigerator during this time if needed).
  • Frost the cake with a second layer of frosting. Decorate however you like! At this point, we added texture around the sides of the cake using a small offset spatula, making diagonal strokes from bottom to top.
  • We added additional piping on top of the cake, piping large frosting shells using a large star (1M) piping tip.
  • Keep the cake in an airtight container or under a cake dome in a cool room in your house for 1-2 days or in refrigerator for longer. If refrigerating, you should remove the cake a couple of hours before serving so that it has time to warm and soften.

Notes

This recipe makes a beautiful two layer cake but it is not as tall as most of the cakes on our site site. (Probably stands approximately 3 inches tall rather than 4.)  We experimented with adding even more flour, etc. to extend it, but doing this made it taste less like brownies. So, a shorter cake is better in this case. (However, you can always double the recipe if you need to!)
These cake layers can be tightly wrapped with plastic wrap, aluminum foil, and frozen for up to three months if baking in advance.
Brownie Cake Mix: So far, our favorite mix for this recipe has been Duncan Hines Double Fudge Brownie Mix (17.6 oz). We also tried Ghirardelli  Double Chocolate Brownie Mix (18 oz), but it tasted more like chocolate cake than brownies.
 We will update if we try this with other mixes.

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5 Comments

    1. Hi Shameka, I would use the back of the brownie mix as an estimate (knowing that this has a bit more batter because of the added flour and sugar). You could also check out Wilton's Baking and Serving Guide: https://blog.wilton.com/cake-baking-serving-guide/

      The Duncan Hines Brownie Mix that I used only makes about 5 cups of batter. I would think an 8x8 or 9x9...something along those lines should work. Or, you could double it for a 9x13.