Cake

1. Preheat oven to 325 degrees and grease and flour a 9 by 2-inch cake pan.
2. In a medium bowl whisk flour, baking powder, salt, and all but 3 tablespoons sugar in mixing bowl. Whisk in 2 whole eggs and 3 yolks (reserving whites), butter, water, vanilla, and Kahlua. Mix until smooth- no lumps remaining.
3. In the bowl of an electric mixer beat the 3 egg whites at medium speed until frothy. Keep whisk attachment still running and slowly add in the 3 tbsp of sugar, beat on medium-high speed until soft peaks for about 1-2 minutes.
4. Stir one-third of egg whites into cake batter. Fold in remaining egg whites to batter until no white streaks remain. Pour into prepared pan and bake until a toothpick inserted in center of the cake comes out clean, 30 to 40 minutes. Cool in pan 10 minutes in pan then invert to a wire rack.

Cream Filling

1. In a large mixer beat heavy whipping cream until light and fluffy, a few minutes at high speed. Scrape whipped cream out, then put mascarpone in bowl and beat that for 2 minutes. Add in powdered sugar, vanilla and Kahlua beat until fully combined. Fold in whipped cream until fully combined.

Coffee Syrup

1. In a small bowl place instant coffee granules, add boiling water and mix until no granules remain. Stir in Kahlua.

Assembly

1. Once the cake is cool cut in half. Place first half on the cake plate. Using a pastry brush brush the cake with the coffee syrup, use half for the first layer. Then scoop half of the cream mixture on top, dust cocoa powder and sprinkle all chocolate chips on top. Place the second cake layer, brush with remaining coffee syrup. Top with remaining cream and dust with cocoa powder. Optional to make chocolate curls, check out this how-to on chocolate curls. Let cake chill and marinate for at least 3 hours before serving. Store in fridge.