5 Secrets to More Color at Home

Cosmic Brownie Cake


Cosmic Brownie Cake

It’s been a little while since we’ve done one of our throwback inspired posts so…. COSMIC BROWNIE CAKE! We’ve already made cosmic brownie pop tarts, eclairs and ice cream sandwiches but this cake is the easiest of them all. Because luckily for us… a sheet cake already looks 90% like a giant Cosmic Brownie!! And there really is nothing better than chocolate cake. So, let’s do this!

Cosmic Brownie Cake

Cosmic Brownie Cake
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Cosmic Brownie Cake

Prep Time20 mins
Cook Time30 mins
Total Time50 mins


  • For the cake use your favorite boxed chocolate cake mix and bake in a 13 x 9 inch pan according to package directions.

  • For the buttercream:

  • 1/2 cup shortening
  • 1/2 cup butter softened
  • 3/4 cup cocoa powder
  • 4 cups powdered sugar
  • 4-8 tablespoons milk
  • 2 teaspoons vanilla extract
  • 1/4 cup rainbow chocolate chip sprinkles


  • Once cake is baked, let cool for about 20 minutes and then remove from pan. Let cool completely.
  • Next, make the buttercream. In the bowl of a stand mixer fitted with the paddle attachment, cream together the shortening and butter till smooth.
  • Add in the cocoa powder and powdered sugar. Mix. Add in the vanilla and then the milk as needed to get a light fluffy texture. Continue to beat on medium for 1 more minute.
  • Spread an even layer of frosting over the entire cake and smooth with an offset spatula.
  • Using a knife or spatula, draw a line across the middle in the frosting.
  • Top the cake with the rainbow chocolate chip sprinkles.
Tried this recipe?Mention @studiodiy or tag #studiodiy!

Cosmic Brownie CakeCosmic Brownie CakeCosmic Brownie Cake

Photos by Jeff Mindell | Recipe by Theresa Rountree

Easy peasy, right!? If you make one for your next bash, be sure to tag #troopstudiodiy so I can see it!!

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