The cookie crust can be made using any of your favorites.  I used a homemade chocolate chip caramel cookie, but you can use any chocolate chip cookie, or a chocolate sandwich cookie or even graham crackers.

As for the filling, I find that creating the whipped cream that thins out the mascarpone with a bit of buttermilk, reinforces the slightly tart mascarpone flavor while yielding a silky smooth consistency.  

The vanilla and the espresso powder set off and heighten the cocoa flavor.

All in all, a simple yet elegant (and surprisingly light) dessert that you can put together in a snap :-) !