1. Make espresso (you may use instant coffee to control the strength of your brew if you don't have an espresso maker.).
2. Add 1/2 cup of sugar to coffee and stir until dissolved.
3. Add Disaronno and set aside.
4. Whip cream with sugar and vanilla until soft peaks form.
5. Fold cream into softened mascarpone.
6. Place a layer of sponge cake slices in the bottom of a 9x9 inch dish.
7. Sprinkle cake slices with half of the espresso syrup and spread half of the cheese filling on top.
8. Repeat for second layer.
9. Cover and chill for at least 8 hours or until the filling has settled.
10. Sprinkle a fine coating of cocoa powder on top and serve immediately.