Preheat the oven to 325 F. Grease the bottom and sides of a 9" springform pan.

Place half of the cake in the bottom of the springform pan. In a bowl, combine the coffee liqueur and the espresso powder. Brush about 1/4 of the espresso mixture onto the cake layer that's in the pan. Brush the second cake layer with 1/4 of the espresso mixture. Set the cake layers and remaining espresso mixture aside.

Fit mixer with paddle attachment. Beat mascarpone, cream cheese and sugar on medium-high speed until smooth and creamy, about 3 minutes. Add eggs, on at a time, beating well after each addition. Mix in the vanilla and the remaining espresso mixture.

Pour half of the batter over the cake layer in the pan, smoothing out the batter to the sides of the pan. Place second cake layer on top and pour in the remaining batter, again, smoothing out to the sides of the pan. The pan will be filled to the top edge.

Place cheesecake pan on a cookie sheet and bake 50-55 minutes, or until light golden brown and center is slightly jiggly. Let cool in the pan on a wire rack for 2 hours. Cover with plastic wrap and refrigerate for at least 6 hours before adding topping.

Using the whisk attachment, beat the heavy whipping cream and the powdered sugar on medium-high until firm peaks are formed. Spread whipped cream on top of chilled cheesecake, then use a sifter to dust the top with cocoa powder.