Zabaglione

Measure ingredients into top of double boiler and place over boiling water. Beat constantly with a rotary beater until mixture thickens and mounds like whipped cream. Remove from heat. Serve hot or chilled in tall parfait glasses or alone or as a topping for sponge cake or fruit. For a little extra elegance, serve with Sherry or, as Grandpa Bob liked, with a glass of Tawny Port.