Brownie Cake
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.
This cake is made from a doctored brownie mix. The crumb is denser than most cake recipes, but softer than most brownie recipes. If you love chocolate, you'll love this recipe.
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!
Table of Contents
Ingredients for Brownie Cake
Here is a quick look at the star players in today's easy brownie cake recipe:
Brownie Mix- This recipe should work well with different brands and types of brownie mix. We've had great results with Duncan Hines Double Fudge as well as Ghirardelli Ultimate Chocolate. (The Ghiradelli is a bit more rich).
Melted Butter adds richness
Sour Cream Just as with doctored cake mix recipes like our Orange Spice Cake and Chocolate Mousse Cake, sour cream adds richness, improves the texture, adds moisture, 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 gives the brownie cake layers a bit more rise.
Unsweetened Cocoa Powder makes for a deeper chocolate flavor
Hot Coffee/Hot Water adds additional richness- the hot temperature helps to develop the cocoa. We like to use hot coffee as it enhances the chocolate flavor- but if you aren't a fan of coffee, hot water works great also!
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.)
- Add the remaining ingredients (eggs, sour cream, fudge packet (if your mix has one), hot water (or hot coffee), and melted butter- and stir until well combined. I prefer to use a rubber spatula for this step.
- This recipe makes approximately 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.
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.
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.
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.
For the top of the cake, I added rows of buttercream shells and then piped a buttercream rosette in the center.
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!)
Here is a peek at the inside of the cake!
Recipe FAQs
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.
Have you made this? We would LOVE for you to leave a ⭐️ rating as well as a comment and photo below! We really appreciate your feedback!
**This recipe has been updated (June 2025), see notes for details!
Brownie Cake
Ingredients
- 1 Box Brownie Mix **See Notes for details
- ½ cup (60g) All Purpose Flour
- ½ cup (100g) granulated sugar
- 1½ teaspoons (6g) Baking Powder
- 2½ Tablespoons (15g) Unsweetened Cocoa Powder
- 1 stick unsalted butter, melted (113g/1/2 cup)
- 1 cup sour cream (we use full fat)
- ½ cup hot coffee (hot water works great also) (we used instant espresso dissolved in hot water)
- 3 large eggs
- Fudge Packet (if your brownie mix comes with one)
For the Chocolate Buttercream
- 3 sticks unsalted butter, softened (339g)
- 6-7 cups confectioners sugar (Adjust up or down to your liking) (805g)
- 1 cup unsweeteded cocoa. Measure, then sift. (82g)
- ½-¾ cup Add slowly, stop when desired consistency is reached. (Add a bit more if needed). (180g)
- 2 teaspoons vanilla extract (8g)
- 1 teaspoon salt (6g)
Instructions
- Preheat oven to 350℉. Grease and flour two 8 inch cake pans. We also like to line them with circles of parchment paper (optional).
- This recipe can be prepared in a large mixing bowl, just as when making brownies from a mix. No electric mixer is 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), hot coffee (or hot water), and melted butter) and stir until well combined. I find it easiest to use a rubber spatula for this step.
- Divide the batter between the two cake pans.
- Bake at 350℉ for 20-25 minutes or until a toothpick inserted in the center comes out clean or with just a few crumbs attached. *Baking times can vary- peek in as you approach the 20 minute mark and adjust time as needed.
- After removing the cake layers from the oven, place the cakes (in their pans) on a wire rack. Cool for 10 minutes before turning out.
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
- Once the layers have cooled, it is time to assemble. Place the first cake layer on a cake plate, spread with frosting, top with the next layer, and frost as usual. We used a large star piping tip (1M or 2D) to decorate the top.
- Store the cake in an airtight container, under a cake dome, or in a bakery box for 1-2 days. Beyond that, we like to refrigerate for freshness.
What size pan would you recommend with a sheet cake instead of layers?
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.
Wow, that's very interesting. Looks fabulous! Awesome as always! :-)
Thanks Teri!
My boyfriend really wants a brownie cake for his birthday, but I can’t find the Duncan Hines double fudge brownie mix. What others do you suggest as he wants it to taste like a brownie! He really likes the Duncan Hines walnut brownie mix.
Hi Anna- I haven't tried many different kinds, but I do like Duncan Hines brownies- I bet the Duncan Hines Walnut Brownie Mix that he likes would work, and will taste like brownies. Let us know how it goes!
What are the measurements of the added ingredients please?
Hi Sharon, the complete recipe with measurements is at the bottom of the post. I hope that you enjoy it!
I didn’t make the icing since I wanted a vanilla buttercream to color, but the cake is delicious! Easy to make and came out dense and chocolatey. Not as fudgey as a brownie but not thicker than normal cake. I used a Ghirardelli double fudge box which didn’t come with a packet of fudge, since my store didn’t have the fudge Duncan Hines. I may seek that out next time instead.
Thanks for your review Katie! So glad that you enjoyed it- your cake looks fabulous! Such a fun design ;0)
what would you do if you wanted to add zucchini to this recipe for a choclate zucchini cake? thanks