For the Cake

Cup of Yum
1. 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.
2. In a medium bowl, stir the flour, cocoa powder, baking powder, and baking soda together. Set aside.
3. 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.
4. Beat the eggs and vanilla extract into the butter mixture until well combined.
5. Beat half of the flour mixture into the wet ingredients. Beat this on low speed just until combined. Do not overmix.
6. Beat in all of the buttermilk just until combined. Again, don’t overmix.
7. On low speed, beat in the remaining flour mixture just until combined.
8. Stir in the melted chocolate by hand until well mixed. Do not use the electric beaters for this step.
9. 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.
10. Bake in oven for 30 minutes or until toothpick inserted in middle of each comes out clean or with moist crumbs.
11. 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.
12. 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.
13. 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

1. 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.
2. 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.
3. 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.
4. 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.
5. Add the third and final layer of cake with the bottom side facing up. You’ll now have a 3-layer cake.
6. 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.
7. Place the lightly frosted cake into the freezer for 10 minutes so the crumb coat hardens up a bit before frosting the next layer.
8. 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.
9. Using a Wilton 1M icing tip and an icing bag, frost swirls along the top border of the cake.
10. 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.
11. Optional: add chocolate sprinkles to the bottom border of the cake.