Tiramisu isn't just for Italian dinners out. Light and airy, it makes a great holiday dessert. Mix together 3 egg yolks with 1 cup powdered sugar, and add 1 cup of Mascarpone cheese, lightly beaten. Beat 3 egg whites into soft peaks, and fold them into the cheesy egg preparation delicately. Soak the ladyfinger biscuits in a mixture of strong coffee and rum, and begin building the dessert by alternating layers of cream and ladyfingers. Store in the fridge to let it firm up a bit. When serving, sprinkle generously with sifted cocoa powder.