Step 1

Preheat the oven to Spray 3 (8-inch) round cake pans with cooking spray. Line the bottoms of the pans with parchment paper, spray the paper with more cooking spray, and set pans aside.

Step 2

Combine the sugar, butter, and oil in a large mixing bowl and whisk until combined. Beat in the eggs and vanilla.

Step 3

Combine the flour, baking powder, baking soda, salt, and cocoa powder in a medium mixing bowl and whisk to combine.

Step 4

Whisk the dry ingredients into the wet ingredients, then slowly add the coffee until just incorporated. Divide batter evenly between the prepared pans and bake for 28 to 32 minutes, until the cakes spring back when touched gently with your fingertip. Let cake layers cool in pans for 15 minutes, then carefully remove from the pans to cool completely on a wire rack.

Step 5

While your cake layers are cooling, make the filling. Place heavy cream in a small pot set over medium heat; heat until cream just starts to steam.

Step 6

Place chocolate in a medium mixing bowl and pour the hot cream over it. Allow to sit for 4 minutes, then whisk until chocolate is melted and mixture is smooth. Cool to room temperature.

Step 7

Beat the cooled ganache with an electric mixer set to low; gradually increase the speed to medium-high. Add the powdered sugar and continue beating until the ganache becomes light and fluffy.

Step 8

If your cake layers have domed, use a long serrated knife to trim them. Place one cake layer on a cake stand or cardboard cake circle and spread half of the whipped ganache over the top in an even layer. (Taping an acetate cake collar around your cake is helpful to prevent the ganache from seeping out. If you don’t have cake collars you can chill your ganache until it sets up but is still spreadable.)

Step 9

Top with a second cake layer and spread the remaining ganache over the top. Top with the third cake layer. Refrigerate cake for 30 minutes (or until ganache is set), then make the frosting.

Step 10

Place the butter in the bowl of a stand mixer fitted with the paddle attachment. Beat until very smooth, about 30 seconds. With mixer set to low, gradually beat in 4 cups of the powdered sugar, the cocoa powder, 3 tablespoons milk, and the salt. Turn mixer to medium and beat until well combined, stopping the mixer occasionally to scrape the sides and bottom of the bowl. If frosting is too thin, add additional powdered sugar; it it’s too thick add additional milk.

Step 11

Pipe (see instructions in post) or spread the frosting over the top and sides of the cake. Take care to get the frosting as smooth as possible so your ganache can drip down the sides of the cake nicely. Use a frosting smoother or an offset spatula to achieve this. Press cookie crumbs around the bottom of the cake if desired. Chill frosted cake overnight.

Step 12

Heat your heavy cream in the microwave for 15 to 20 seconds, until very hot but not boiling. Place your white chocolate in a small bowl and pour the hot cream over the top. Let sit for 4 minutes, then whisk until completely smooth. If ganache is too thick to drip nicely, pop it in the microwave for a few seconds.**

Step 13

Transfer to a squeeze bottle (or a large zip-top plastic bag with one corner snipped off) and squeeze a line of white chocolate around the perimeter of the chilled cake, squeezing harder in some places to create drips down the side of the cake. Use the remaining ganache to fill in the top of the cake. Refrigerate until ganache is set, then make the dark chocolate drip.

Step 14

Heat the heavy cream in the microwave for 30 to 40 seconds, until very hot but not boiling. Place the chopped chocolate in a large bowl. Pour the warm cream over the chocolate and let it sit for 4 minutes. Whisk until completely smooth.

Step 15

Transfer the ganache to a plastic squeeze bottle (or a large zip-top plastic bag with one corner snipped off). Squeeze a circle of ganache around the edge of the cake on top of the white chocolate, applying a little extra pressure at certain points to create drips. Carefully spread the remaining ganache over the top of the cake. If desired, decorate the top of the cake with chocolate candies. Refrigerate to set the ganache, then slice and serve.