Step 1

Preheat the oven to 325°Fahrenheit. Grease two 8-inch round cake pans and line the bottoms with parchment paper.

Step 2

Add the flour, baking powder, baking soda, and salt to a medium bowl. Whisk to combine.

Step 3

Melt butter in a large saucepan over medium heat. Add the cocoa and stir until blended. Stir in the granulated and brown sugar.

Step 4

Remove the pan from heat and stir in buttermilk, coffee, and vanilla. Whisk in the eggs one at a time until blended.

Step 5

Stir in the flour mixture until combined. Pour the batter into prepared pans.

Step 6

Bake for 35-40 minutes or until a toothpick inserted in the center is removed cleanly. Cool the cakes in the pans for 10 minutes before removing to wire racks.

Step 7

To make the pudding, combine the sugar, cornstarch, and salt in a saucepan. Gradually whisk in the milk. Cook over medium heat, stirring constantly, until mixture thickens and boils. Remove from the heat. Stir in the chocolate and vanilla until smooth. Cover and refrigerate until cold.

Step 8

To make the frosting, melt the chocolate and butter in a double boiler, stirring until smooth. Remove from heat. Whisk in hot water all at once. Whisk in the corn syrup and vanilla. Refrigerate for 25-30 minutes or until spreadable.

Step 9

To assemble the cake, cut each cake horizontally in half to create four layers. Set one layer aside for crumbs. Place one layer on a serving plate. Spread with half of the pudding. Add the second layer and the remaining pudding. Top with the third layer.

Step 10

Frost the top and sides with chocolate frosting. Crumble the reserved cake layer and press the crumbs onto the top and sides of the cake. Refrigerate until serving.