3 tbls corn starch
½ tsp kosher salt
1 tsp baking soda
8 tbls unsalted butter, softened
1-½ cups sugar
3 whole large eggs
½ cup sour cream,room temp
2 tsp vanilla
For the coffee extract:
2 tbls instant coffee powder
2 tbls boiling water
For the coffee syrup:
1/2 cup water
1/3 cup sugar
1 tablespoon Kahlua
For the filling and frosting:
1 8-ounce container mascarpone
1/2 cup confectioners’ sugar, sifted
1 1/2 tsp pure vanilla extract
1 tbls Kahlua
1 cup cold heavy cream
3.5 ounces semi-sweet chocolate, finely chopped chocolate-covered espresso beans, for decoration (optional)
For the cake:
Sift together flour, salt, baking soda, and corn starch.
Cream 8 tablespoons butter with the sugar until light and fluffy. Add eggs one at a time, mixing well after each addition. Add sour cream and vanilla and mix until combined. Add sifted dry ingredients and mix on low speed until just barely combined.
Pour into greased and floured 9-inch cake pan. Bake at 350 degrees for 35 to 40 minutes, or until golden brown and a toothpick inserted in the center comes out clean. Remove from the cake from the pan when you pull it out of the oven, and place on a cooling rack and allow it to cool completely.
To make the extract:
Mix together the boiling water and coffee powder in a small bowl until blended. Set aside.
To make the syrup:
Stir the water and sugar together in a small saucepan and bring just to a boil. Take off the heat and stir in 1 tbls of the coffee extract and the Kahlua; set aside.
To make the filling and frosting:
Put the mascarpone in a mixer bowl and whisk for a couple of minutes, add the sugar, vanilla, and liquor and whisk just until blended and smooth.
Whip the heavy cream until it holds firm peaks. Using a rubber spatula stir about one quarter of the whipped cream into the mascarpone. Fold in the rest of the whipped cream with a light touch.
To assemble the cake:
With a serrated knife cut the cake in half.
Place half cut side up on a platter. Using a small spoon drizzle about 1/3 of the espresso syrup onto half of the cake. Spread some of the mascarpone filling onto that layer (about 1 1/2 cups). Sprinkle about half of the chopped chocolate over the filling and press it into the mixture. Now take the other layer, and on the cut side drizzle about half of the remaining syrup or more depending on how soaked you want the cake to be. Then turn it over and position it over the filling.
Frost the cake:
Add about 1 to 1/2 tbs.(depending on how much coffee flavor you like) of the espresso extract to the remaining filling mixture and whisk so that it is completely incorporated.
Take the frosting and put it to the top of the cake, spread it out to the edges and onto the sides. Refrigerate for at least three hours. Decorate with remaining chopped chocolate and chocolate espresso beans.
Enjoy!
