Brownie Birthday Cake
This Brownie Birthday Cake recipe is made with thick, fudgy, and gooey brownies from a box mix layered between homemade vanilla buttercream frosting and rainbow sprinkles. A delicious alternative to a classic birthday cake recipe: a birthday cake from brownie mix!
Equipment
- Stand mixer (or hand mixer + mixing bowl)
- Spatula
- Measuring cups
- 8" round cake pans
- Parchment paper
- Scissors
- Piping bag
- Cake turntable
Ingredients
Brownies
- 2 boxes Brownie mix and brownie mix ingredients
- Half-and-half* swap for water in brownie mix
- Shortening to grease the pan
Buttercream Frosting
- 7 cups Confectioner's sugar
- 2 cups Butter unsalted, extra soft*
- 1 and 1/2 tsp Salt
Instructions
- Preheat the oven to 325 degrees.
Prepare The Baking Pans
- Using a pencil, trace the bottom of an 8" round cake pan on a piece of parchment paper three times.
- Cut out the three circles, leaving about an extra inch of room around the circle (this will make it easier to remove the baked brownies from the pan).
- Grease the inside of the cake pans using shortening.
- Place a piece of parchment paper in the bottom of each greased pan (make sure the side with the pencil markings is face down).
Bake The Brownies
- Prepare the brownie box mixes according to the package instructions, with the following two adjustments:
- Use half-and-half instead of water
- Divide the brownie batter across three 8" baking pans.
- Bake for 23-25 minutes (you can bake up to two pans at a time).
- Let the baked brownies cool completely in the pans on top of a wire rack.
- Carefully insert the end of a rubber spatula between the brownies and the pan, to help loosen the brownies.
- Pinch a section of the parchment paper, and lift it up just enough to slide your other hand underneath the brownie to lift it out of the pan and place it on a flat surface (like a cutting board).
Make The Buttercream Frosting
- Beat the super-soft butter until it is extra creamy, for about a minute or two, using a hand mixer or stand mixer.
- Add the salt and about half of the confectioner's sugar and mix to incorporate.
- Scrape the sides and add the remaining confectioner's sugar and mix until the frosting is light and fluffy for about 2 - 4 minutes.
- Transfer the icing to a large piping bag using a spatula.
- Using scissors, cut the end of the piping bag once you are ready to begin frosting the cake.
Frost The Brownie Birthday Cake
- Place one of the brownies faced up on a cake decorating turntable.
- Hold the piping bag with frosting in your dominant hand and frost the top of the brownie. Then add rainbow sprinkles.
- Place a second brownie faced down on top of the icing. Frost the top of the brownie and add rainbow sprinkles.
- Repeat this step with the last brownie.
- Lightly frost the side of the brownie cake and add rainbow sprinkles.
Notes
Cook time assumes you cook two pans at once (23-25 minutes), and cook the third pan by itself (23-25 minutes), for a total of 50 minutes.
* Amount depends on the brownie mix instructions.
** If leaving your butter at room temperature doesn't do the trick, I like to set my on the oven while it is preheating. Just make sure you keep an eye on it so that it doesn't melt. I do not recommend microwaving the butter. I promise it is worth the wait! If you feel that it's not getting to the super-soft consistency, you can add a 1/2 tablespoon to 1 tablespoon of milk, half and half, or heavy cream when you are beating the butter in the mixer.