Nearly 100 friends and admirers of Luigi Zara, chef of the Georgetown Club, responded to an invitation to help the chef celebrate his 60th birthday early this month. Zara is a larger-than-life cook of the classic school with a personality to match his talent. He supervised preparation of a banquet that featured an elegant game consomme, an original preparation of crab, beef and a salad highlighted by radicchio, a rare, red lettuce the Chef's wife, Ada, grows at home. In the midst of a flurry of toasts, Chef Zara, appeared with his own birthday cake, topped by a miniature chef's toque . Sparkling wine was served, of course, plus -- just as naturally -- another dessert. The meal and the wine are gone, but the recipe lingers on. This is it. LUIGI ZARA'S COLD ORANGE ZABAGLIONE (8 or 10 servings) 8 large egg yolks 10 ounces granulated sugar 1/4 cup Strega liqueur (or Galliano) 1 tablespoon vanilla extract Juice of 2 oranges 1 packet (6-ounces) orange gelatin mix 1 quart whipped cream

In an electric mixer blend yolks with sugar until lemon-colored and add vanilla. Mix gelatin, liqueur and orange juice in a pan and sitr over low heat just until gelatin has dissolved. Remove from stove and add to yolk mixture. Mix for about 2 minutes. Whip the cream until it forms firm peaks and fold into other ingredients. Spoon into individual dishes or a large dish and refrigerate.