Preheat oven to 350 degrees
Sift cake flour, baking powder, salt in bowl. Set aside.
Beat butter until creamy with a paddle attachment with mixer or electric mixer for three minutes.
Cream sugar and butter for three minutes.
Add eggs one at a time and beat for a minute each. Add vanilla
On low speed add in buttermilk and dry ingredients in three additions. Begin and end with flour mixture.
Bake for 28 to 30 minutes at 350.
ESPRESSO EXTRACT INSTRUCTIONS (See Note)
Mix together until blended. Set Aside.
ESPRESSO SYRUP INSTRUCTIONS (See Note)
Bring sugar and water together just until boiling. Add above espresso extract and liqueur or brandy. Set aside.
FILLING AND FROSTING INSTRUCTIONS
Blend mascarpone, confectioner's sugar, vanilla and Kahlúa or brandy and whisk just until smooth.
Whip heavy cream until it holds stiff peaks. Using a rubber spatula stir in 1/4 of whipped cream into the mascarpone.
Gently fold in remaining whipped cream.
FOR A FOUR LAYER CAKE
Bake cakes in two 9 inch pans. Divide into 4 equal parts.
Using pastry brush, brush some espresso syrup over bottom layer, saving 1 tablespoon of the syrup for the final frosting.
Shave chocolate. You will use this for each layer, sparingly.
Save some of this for the final decorating step.
Spread some mascarpone cream over and gently press some of the chopped chocolate into the filling.
Use 1 cup or so only for this step, saving the frosting for the final layer.
Repeat with each of first three layers.
FINAL FROSTING INSTRUCTIONS
Whisk the remaining 1 tablespoon of espresso extract into the remaining mascarpone filling. Apply frosting on sides and top.
Decorate with espresso beans or my personal choice, some shaved chocolate.
Refrigerate, but serve a little less chilled. Take out 30 minutes prior to serving.