In a bowl, combine the graham cracker crumbs, melted butter, and sugar. Press the mixture into the bottom of a 9-inch springform pan to form the crust.
In a large mixing bowl, beat the cream cheese until smooth. Add sugar, flour, and vanilla extract; mix well.
Add eggs one at a time, beating well after each addition. Stir in sour cream.
In a separate bowl, combine brewed coffee and coffee liqueur. Gradually add the coffee mixture to the cream cheese mixture, mixing well.
Gently fold in the mascarpone cheese until evenly combined.
Pour the batter over the crust in the springform pan. Smooth the top with a spatula.
Bake for 55-60 minutes or until the center is set and the top is lightly browned.
Allow the cheesecake to cool in the pan on a wire rack. Refrigerate for at least 4 hours or overnight.
Before serving, dust the top with cocoa powder.
Notes
For an extra touch, garnish the chilled cheesecake with chocolate shavings or espresso beans before serving.