Preheat oven to 350 degrees F (175 degrees C). Place a pan of water on the bottom of oven.
Crush the package of ladyfingers to fine crumbs. Mix the melted butter into the crumbs. Moisten with 2 tablespoons of the coffee liqueur. Press into an 8- or 9-inch springform pan.
In a large bowl, mix cream cheese, mascarpone, and sugar until very smooth. Add 2 tablespoons coffee liqueur, and mix. Add the eggs and the flour; mix SLOWLY until just smooth. The consistency of the mascarpone can vary. If the cheesecake batter is too thick, add a little cream. Do not overmix at this point. Pour batter into crust.
Place pan on middle rack of oven. Bake for 40 to 45 minutes, or until just set. Open oven door, and turn off the heat. Leave cake to cool in oven for 20 minutes. Remove from oven, and let it finish cooling. Refrigerate for at least 3 hours, or overnight. Right before serving, grate the semi-sweet chocolate overtop.