Chocolate-Espresso Tart
A cocoa shell forms a crisp foundation for two silky-smooth fillings: an even layer of creamy, tangy mascarpone cheese and gorgeous rosettes of espresso-flavored chocolate ganache. The flavors are strong, yet not particularly sweet; if you prefer, you can mix one to two tablespoons of sugar into the mascarpone filling. To produce perfect ganache every time, make sure the mixture is at room temperature before you start to beat it with an electric mixer. Any warmer or colder, and the mixture may seize or become grainy.