Weigh out the ingredients
I
For the cake layers, you'll need flour, sugar, baking powder, salt, butter, egg, buttermilk, vanilla, and oil.
Weigh out the ingredients
II
For the chocolate frosting, you'll need chocolate, butter, powdered sugar, vanilla, heavy cream, cocoa powder, and salt.
In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, sugar, baking powder, and salt. Cut up the butter into small cubes and add to the flour mixture. Mix on low speed until it resembles wet sand.
Cut the butter into the dry ingredients
III
Add the oil, buttermilk, egg, and vanilla, and mix until just combined.
Mix in the wet ingredients
IV
Scrape down the bowl, then divide the cake batter between the prepared round cake pans. Bake for 22-25 minutes or until a toothpick inserted comes out clean.
Bake
V
Immediately turn the cakes out onto a wire rack to cool completely. Once cool, wrap the cakes in plastic wrap and freeze until ready to decorate. (Frozen cake layers will be much easier to frost!)
Cool, then freeze
VI
Place the butter over medium heat. As it melts, stir it with a rubber spatula to encourage even cooking. Once the butter has fully melted, it will alternate between rapid large bubbles and gentle small foamy bubbles. The butter will be ready once it turns a dark golden color and the fat solids have darkened and settled at the bottom of the pan.
Brown the butter
VII
Add the remaining ingredients. Stir constantly until everything is melted. Pour the mixture through a fine mesh sieve into a large bowl. Chill for at least one hour or overnight.
Add remaining ingredients
VIII
Place the first cake layer on a cake stand. Use a 3 tablespoon cookie scoop to add 3 scoops of frosting. Use an offset spatula to spread into an even layer. Repeat with the second cake layer.
Assemble the cake
IX
Add the last cake layer and top with a few more scoops of frosting. Use the offset spatula to smooth out the top, and spread the excess all over the sides. Continue decorating the cake as desired. Top the cake with confetti sprinkles, and enjoy!
Decorate
X