Step 1

Preheat the oven to Spray 3 (8-inch) round cake pans with cooking spray. Line the bottoms of the pans with parchment, spray the parchment 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 until combined.

Step 4

Whisk the dry ingredients into the wet ingredients, then slowly add the coffee (or flat cola) 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.

Step 5

Cool in the pans on a wire rack for 15 minutes then invert cakes onto the rack and peel off parchment paper. Let cake cool completely before proceeding. (Once cooled you can wrap tightly in plastic wrap and store at room temperature for up to 1 day.)

Step 6

Place the chocolate in a medium heatproof bowl. Place 1/2 cup of the heavy cream in a small saucepan set over medium heat and bring cream to a simmer. Do not allow to boil. Pour hot cream over the chocolate and let stand for 3 minutes. Add the corn syrup then whisk until chocolate melts and mixture is smooth. Let stand at room temperature until cool but not firm, about 30 minutes.

Step 7

Place sugar and the remaining 3/4 cup of heavy cream in a large mixing bowl. Beat with an electric mixer set to high speed until the cream holds soft peaks. Stir one quarter of the whipped cream into the cooled chocolate mixture using a rubber spatula until combined. Gently fold in remaining whipped cream.

Step 8

Microwave white chocolate at 50% power in 15-second intervals, stirring after each interval, until chocolate is melted and smooth. Allow to cool for several minutes.

Step 9

Beat cream cheese and butter together in a medium mixing bowl until light and fluffy. Beat in melted white chocolate until combined. Add powdered sugar and salt and beat on low speed until combined. Turn mixer to high and beat until very fluffy, 3 to 4 minutes.

Step 10

Place the butter in the bowl of a stand mixer fitted with the paddle attachment. Beat on medium speed until very smooth and creamy. Turn mixer to low and beat in cocoa powder, then gradually beat in 4 cups of powdered sugar. Beat 1 to 2 minutes more. Add 3 tablespoons of milk, vanilla, espresso powder (if using), and salt and beat to combine. Turn mixer to medium and beat until frosting is smooth. Add additional powdered sugar if frosting is too thin or additional milk if it is too thick.

Step 11

Trim the tops of the cake layers so they’re even—a long serrated knife is your best choice of utensil here. Place 1 cake layer on a cake circle. Fit a pastry bag with a 1/2-inch round tip and fill the bag with about 1 cup of frosting.

Step 12

Spread half of the white chocolate filling over the top of the cake—don’t go all the way to the edge of the cake. Pipe two lines of frosting around the edge of the cake. (This is the dam that will hold your mousse inside the cake.) Place a little less than half of the chocolate mousse on top of the white chocolate filling. You want enough to fill in the dam but not so much to overflow. Make sure the mousse reaches the edge of the buttercream, then smooth the top of the mousse. Refrigerate cake layer for 20 minutes.

Step 13

Repeat the filling instructions from the previous layer. You may not be able to use all of the mousse; keep the remainder as a well-deserved treat. Again refrigerate cake for 20 minutes.

Step 14

Top with the remaining cake layer and. Frost cake with chocolate buttercream, then refrigerate the cake while you make the glaze.

Step 15

Place the chocolate in a small heat-proof bowl. Heat the glaze in a small saucepan over medium heat until it just begins to steam. Pour over the chocolate and let sit for 3 minutes. Whisk until mixture is smooth. Let cool for 5 to 10 minutes (until it’s thick but still pourable) then pour over the frosted cake.  Alternatively, you can pour the glaze into a plastic squeeze bottle and squeeze a circle of glaze around the edge of the cake.  Squeeze a little more glaze out in some places to create drips.  Pour the remaining glaze over the cake and smooth the top. Refrigerate to set the glaze then slice and serve.