Tiramisu("pick me up") is a modern version of a dessert first created in Siena, where it was called zuppa del Duca (the Duke's soup!). From there it migrated to Florence, where it became very popular in the nineteenth century among the many English people who came to live in the city at that time. And so it was called zuppa inglese--English soup. Only recently, the same dessert with some variation--chiefly the substitution of rich mascarpone cheese for the original custard--has come to be called tiramisu. Make a zablione by beating the egg yolks and sugar in the top of a double boiler until ivory colored. Add 1/3 cup liquor and whisk over gently simmering water until the mixture begins to thicken. Let cool. Stir the coffee into the mascarpone. Whip the cream to soft peaks. Beat the egg white until stiff. Fold the egg white into the zabaglione. Dip the lady fingers into the remaining liquor and arrange in a single layer in the bottom of a 9 in. bowl. Cover them with half the mascarpone, then half the zabaglione and half the cream. Repeat the layers, finishing with the cream. Refrigerate for several hours before serving.