One of Italy's great gifts to the rest of the world, zabaglione is an ethereal dessert made by whisking together egg yolks, wine (traditionally marsala) and sugar. This beating is done over simmering water so that the egg yolks cook as they thicken into a light, foamy custard. Traditional zabaglione must be made just before serving. (There is also a frozen version.) The warm froth can be served either as a dessert by itself or as a sauce over cake, fruit, ice cream or pastry. In France it's called sabayon or sabayon sauce.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.