Sostanza's Tiramisu

Cream mascarpone with the sugar, egg yolks, vanilla and 2 tablespoons Cognac.

In another bowl, whip the cream until stiff. Carefully fold in the mascarpone mixture. Keep cool.

When the espresso is cool, add the remaining 4 tablespoons of Cognac.

Using a 9-by-16-inch sheet pan (it should have 1-inch edges), spread a quarter-inch layer of the mascarpone cream about five inches wide down the middle. (There will be space on either side of the pan.) Dip the biscuits lightly into the espresso and place in a row atop the mascarpone mixture the entire length of the pan. Using a spatula, spread a half-inch layer of the mascarpone cream over the biscuits. Sprinkle with a fourth of the grated chocolate. Repeat for 2 more layers, topping the final layer with the grated chocolate. Facing the biscuits in different directions in each layer will make the dessert firmer for slicing. Chill several hours to overnight.