Coffee Chocolate Cake (The Cake Slice Bakers)

Instructions

1. Preheat the oven to 350°. Spray three 8-inch round cake pans and line with parchment paper.
2. For the Cake: In a large mixing bowl, cream together the butter and sugar. Add the eggs, one at a time, mixing well after each addition. Dissolve the instant coffee in the warm milk and stir until completely blended. Turn mixer on low and add the milk mixture into the batter. Mix until combined.
3. In a separate bowl combine all of the dry ingredients: flour, cocoa powder, baking powder, and salt. Remove the bowl from the stand mixer and sift the flour mixture into the batter. Return the bowl to the stand and mix on low until it is just combined completely (don't overmix).
4. Divide the batter evenly among the three pans and bake for 20-22 minutes (until a toothpick comes out clean). Cool the layers in the pan on a rack.
5. For the coffee custard: in a small bowl, whisk together the egg yolk and sugar until completely combined (will be fairly dry and sandy at this point). Combine the cornstarch and water in a small cup to form a slurry, then add to the yolk mixture, whisking to combine. In a small saucepan, whisk together the milk, flour, and instant coffee. Cook on medium-low heat, stirring constantly until the milk is steaming hot.
6. In a thin, slow stream, drizzle the hot milk mixture into the egg mixture, whisking constantly so the eggs don't scramble. Return the milk and egg mixture to the saucepan and cook over medium heat, again stirring constantly until it thickens (2-3 minutes).
7. Remove the custard from the heat, add the 2 tablespoons of butter and stir until the butter is melted and completely incorporated. Pour custard into a medium bowl and cover with plastic wrap, pressing the wrap lightly to cover the top of the custard (this is so it won't form a skin while cooling). Refrigerate for at least an hour.
8. For the French buttercream: Whisk egg yolks in a stand mixer (with whisk attachment of course) on high until thick and pale yellow (about 4 minutes).
9. Meanwhile, put the water and sugar in a small saucepan - stir until thoroughly mixed. On medium heat, cook the syrup, sweeping a wooden spoon around the bottom (not sides) occasionally, until it reaches about 238° on a candy thermometer. Remove from heat.
10. Slowly drizzle the syrup into the egg mixture with the mixer on medium speed. After the syrup is incorporated, turn the mixer to high speed and whisk for 5 minutes until the mixture has cooled and thickened (feel the bottom of the mixing bowl and it will get less and less warm).
11. Add the softened butter, one tablespoon at a time and mix in on medium for 15 to 20 seconds between each addition. This is an important step and takes time, but make sure and put 1 tablespoon at a time. After completing the butter step, drizzle in the melted chocolate and whisk on high for 1 minute.
12. Transfer about half of the frosting into a pastry bag with a star tip (or use a zip lock bag with a corner cut about ½" up). For the first two layers, pipe a 'barrier' around the edge of the cakes layer to keep in the cooled custard. Spoon in and spread half the custard on the bottom two layers. Put the third/top layer on, make sure the cake looks level, and frost the top and sides with the buttercream.
13. Pipe dollops on top of the cake if you have extra frosting in the piping bag if you'd like. Drizzle thin lines of melted chocolate across the top if desired. Garnish with coffee beans or how ever you'd like.