Tiramisu is a modern Italian dessert that means pick-me-up! I first was taught this dessert by a woman in the kitchens of the restaurant at Badia a Coltibuono in Chianti.
Combine the coffee with 1 Tbs. sugar in a wide flat bowl. Set aside.
To make the cream mixture, in a mixing bowl with a whisk beat the yolks with half the sugar until very thick and light in color. With a wooden spoon, stir in the mascarpone cheese until smooth. Add the rum, lemon juice, and vanilla.
In another bowl, whip the cream with the remaining sugar and fold into the cheese mixture. In another bowl, whip the egg whites with a few grains of salt until stiff but not dry, and fold into the cheese mixture, as well.
To assemble, dip half of the ladyfingers, one at a time, in the coffee mixture and line a long flat serving dish with them. Spoon a layer of the cream mixture over these. Add another layer of dipped ladyfingers and spoon the remaining cream over the top. Cover the whole thing with a thick layer of grated unsweetened chocolate or sieved unsweetened cocoa. Chill in the fridge. This dish can be made up to three days ahead.