Step 1

Preheat the oven to 350F. Spray three 6-inch round cake pans with cooking spray. Line the pans with parchment paper and lightly spray again.

Step 2

In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Add the eggs, buttermilk, oil, and vanilla. Using a handheld electric mixer, beat on medium speed until combined. Pour in the hot coffee and beat on medium speed until just combined. Divide the batter among the prepared pans.

Step 3

Bake until a toothpick inserted into the centers of the cakes comes out clean, 27 to 30 minutes. Let the cakes cool in the pans for 10 minutes. Then run a knife around the edges of the pans and turn the cakes out onto a cooling rack. Peel off the parchment paper and let them cool completely.

Step 4

In a stand mixer fitted with the paddle attachment, beat the butter on high speed until smooth, about 1 minute. Reduce the speed to low and gradually add the confectioners’ sugar. Add in the vanilla and milk and beat until combined. Using a rubber spatula, scrape down the sides of the bowl. Beat the frosting on medium-high speed until it is smooth and fluffy, about 3 minutes.

Step 5

Transfer 1 tablespoon of the frosting to a small plastic zip-top bag and cut off a small tip.

Step 6

Transfer 1 tablespoon of the frosting to a separate bowl and color it black with the black gel food color. Transfer it to a small plastic zip-top bag and cut off a small tip.

Step 7

Transfer ½ cup of the frosting to a separate bowl and color it pink with the pink gel food color. Transfer it to a small plastic zip-top bag and cut off a small tip.

Step 8

Using a cake leveler or a serrated knife, cut the rounded tops off the cakes. Pipe about 1 tablespoon of the remaining white frosting onto a 6-inch cake board, and then place one cake layer on top. Pipe a layer of white frosting onto the cake and spread it evenly with an offset spatula. Place a cake layer on top, pipe on a layer of white frosting, and spread it evenly with an offset spatula. Top with the final cake layer, cut-side down. For the crumb coat, pipe a thin layer of white frosting over the entire cake and spread it evenly with an offset spatula. Refrigerate the cake for 15 minutes.

Step 9

Pipe white frosting over the entire cake and spread it evenly with an offset spatula. Run an icing smoother around the sides of the cake to smooth the frosting. Using an offset spatula, bring the frosting from the top edges of the cake toward the center to create a flat top.

Step 10

Using the reserved pink frosting, pipe the outline of a scallop border around the top edge of the cake. Then fill in the scallops with more pink frosting, and pipe pink frosting to cover the top of the cake as well. Refrigerate the cake until the frosting is firm and doesn’t stick to your finger when tapped, about 20 minutes.

Step 11

Using an offset spatula, carefully smooth the scallops and the top of the cake. Press the rainbow sprinkles over the pink frosting.

Step 12

For the ears, use a serrated knife to cut off about ⅛ inch from the bottom of two of the chocolate sandwich cookies to create a flat edge. Place the ears on top of the cake toward the front.

Step 13

Separate the two remaining chocolate sandwich cookies and scrape off the cream filling. Use a serrated knife to cut two of the chocolate cookies into ovals for eyes, and cut a third chocolate cookie into a triangle for a nose. (You can eat the remaining cookie!) Using the reserved white frosting, pipe dots onto the eyes for pupils.Press the eyes and nose onto the front of the cake; use the reserved black frosting to pipe on a smile. Press a pink jelly bean on each side of the eyes for cheeks.