Step 1

To make cake: Preheat oven to 325º. Coat three 8 or 9 inch cake pans with non-stick spray and then line bottom of pans with rounds of parchment paper. Note that this recipe makes 3 layers, but only 2 are needed for this cake.

Step 2

Put very hot coffee into a medium bowl. Add chocolate, let sit 5 minutes, then whisk until fully melted Set aside.

Step 3

In a stand mixer, combine 3 eggs and 1 extra yolk with the sugar and beat until light and pale yellow, approximately 3 minutes. Add the oil, buttermilk and vanilla and beat until combined. Add flour, cocoa powder, baking soda and powder and salt and beat until combined. Add chocolate mixture and mix until just fully incorporated.

Step 4

Divide batter between pans and bake in middle of the oven until a toothpick inserted in a center comes out clean, about 40-45 minutes. Remove to cooling rack. Cool for  about 10 minutes, then remove from pans and allow to cool completely. Carefully peel off parchment. Wrap and freeze one of the 3 layers to use at a later time. You can make a 3 layer cake, but you will need more filling and frosting.

Step 5

To make filling: Melt cream and white chocolate in microwave, stopping and stirring at 30 second increments till smooth and melted. Refrigerate mixture till cool and thick (you do not want the filling to be hard, but if it is too runny, it will run down sides of cake when second layer is placed over it).

Step 6

To make frosting:

Step 7

Place chopped chocolate into a microwave safe bowl. Microwave, stopping to stir frequently, until chocolate is melted and smooth. Let the chocolate cool until lukewarm, stirring occasionally.

Step 8

Beat butter in large bowl until smooth and creamy (I used my stand mixer with the paddle attachment). Sift powdered sugar over butter and beat until well blended, about 2 minutes. Beat in vanilla. Add melted chocolate and beat until well blended, scraping down sides of bowl as needed.

Step 9

Frost as desired.