Once in a rare while, we discover a formula for a dish that seems the ultimate, the definitive, the ne plus ultra of its kind. Over the years we have printed recipes for a score or more desserts called mousse au chocolat, or chocolate mousse. We are convinced that the finest chocolate mousse creation ever whipped up in our kitchen is the one printed here. As if you didn't know, mousse means foam in French. This mousse is the foamiest.

Mousse au chocolat

(Chocolate mousse) 1/2 pound sweet chocolate 6 large eggs, separated 3 tablespoons water 1/4 cup sweet liqueur such as chartreuse, amaretto, mandarine or Grand Marnier 2 cups heavy cream 6 cups heavy cream Whipped cream for garnish Grated chocolate for garnish

1. Cut the chocolate into 1/2 inch pieces and place the chocolate in a saucepan. Set the saucepan in hot, almost boiling water and cover. Let melt over low heat.

2. Put the yolks in a heavy saucepan and add the water. Place the saucepan over very low heat while beating vigorously and constantly with a wire whisk. Experienced cooks may do this over direct heat such as a low flame or electric burner. It may be preferable, however, to use a metal disc such as a Flame-tamer to control the heat. In any event, when the yolks start to thicken, add the liqueur, beating constantly. Cook until the sauce achieves the consistency of a hollandaise or a sabayon, which it is. Remove from the heat.

3. Add the melted chocolate to the sauce and fold it in. Scrape the sauce into a mixing bowl.

4. Beat the cream until stiff, adding 2 tablespoons of the sugar toward the end of beating. Fold this into the chocolate mixture.

5. Beat the whites until soft peaks start to form. Beat in the remaining sugar and continue beating until stiff. Fold this into the mousse.

6. Spoon the mousse into a crystal bowl and chill until ready to serve. When ready to serve, garnish with whipped cream and grated chocolate.

Yield: 12 or more servings.