Brooklyn Blackout Cake

Directions

1. In a small heavy saucepan, mix sugar, cornstarch and salt. Whisk in milk. Cook and stir over medium heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer. Stir in chocolate until melted. Transfer to a bowl; stir in vanilla. Cool slightly, stirring occasionally. Press plastic wrap onto surface of pudding. Refrigerate, covered, 2 hours or until cold.
2. Preheat oven to 325°. Line bottoms of two greased 8-in. round baking pans with parchment; grease paper. In a small bowl, whisk flour, baking powder, baking soda and salt. In a large saucepan, melt butter over medium heat. Add cocoa; cook and stir until blended. Stir in sugars. Remove from heat; stir in buttermilk, coffee and vanilla. Whisk in eggs, one at a time, until blended. Stir in flour mixture just until combined.
3. Transfer batter to prepared pans. Bake 35-40 minutes or until toothpick inserted in center comes out clean. Cool in pans 10 minutes before removing to wire racks; remove parchment. Cool completely.
4. For frosting, in the top of a double boiler or a metal bowl over hot water, melt chocolate and butter; stir until smooth. Remove from heat. Whisk in hot water, all at once. Whisk in corn syrup and vanilla. Refrigerate 25-30 minutes or just until spreadable.
5. Using a long serrated knife, cut each cake horizontally in half. Place a cake layer on a serving plate. Spread with half of the pudding. Repeat layers. Top with a third cake layer. Spread frosting over top and sides of cake.
6. Crumble remaining cake layer; sprinkle over top and sides of cake, pressing lightly to adhere. Refrigerate leftovers.