Make the crust first. Preheat oven to 350 degrees.
Butter an 8-inch springform pan.
Stir butter and espresso powder in small bowl until combined.
Stir in crumbs until crumbs are evenly moistened.
Pat evenly over bottom of prepared pan.
Bake 10 minutes, cool on wire rack. Keep oven on.
Tightly cover outside bottom and sides of springform pan with heavy-duty foil.
Make the filling. Beat cream cheese and mascarpone in large mixer bowl at medium-high speed until light and fluffy.
Scrape sides with rubber spatula and continue mixing until completely smooth (about 3 minutes).
Reduce speed to medium and beat in sugar, vanilla and salt.
Add eggs, one at a time, beating just until blended after each addition.
Pour 4 cups of filling over crust in prepared pan, and place in large roasting pan.
Dissolve espresso in hot water. Fold into remaining filling with brandy and grated chocolate.
Spoon mixture evenly over filling in pan; smooth top with spatula.
Place pan on oven rack. Pour enough hot water into roasting pan to come 1-inch up side of springform pan.
Bake 1-1/4 hours or until center is just set.
Remove cheesecake from water bath.
Cool completely on wire rack. Remove foil, cover and refrigerate overnight.
Just before serving, run knife around edge of pan and remove sides.
Sprinkle Unsweetened Chocolate over top of cheesecake. (I use a sifter to do this).