In a bowl, beat the egg yolks.
In another bowl, beat the mascarpone. Stir in the egg yolks until blended.
In a mixing bowl, beat the egg white until soft peaks form. Add the sugar, little by little, and continue beating until stiff.
In another bowl, beat the chilled cream until soft peaks form. Fold in the egg whites.
Fold the cream-egg white mixture into the mascarpone mixture, taking care not to overmix and break the air bubbles in the beaten egg whites and cream. These bubbles, invisible to the naked eye, are responsible for making the tiramisu as light as a cloud.
Spread the pieces of lady fingers in a plate large enough to hold them in a single layer. Sprinkle the espresso over them.
Place two heaping tablespoonfuls of the cheese-cream mixture into wine glasses. Cover with the coffee-soaked lady fingers. Top with two more tablespoonfuls of the cheese-cream mixture then sprinkle with grated or shaved chocolate.
Chill for an hour before serving.