Marquise Au Chocolat(Avec Une Sauce De Crème a L'Anglaise)

Melt chocolate in a double boiler; add a few drops of water if necessary to smooth out chocolate.

Let cool; meanwhile, beat yolks, sugar and butter until smooth and silky.

Add this mixture to the cooled chocolate; it should be smooth and thick, but not stiff.

Gently fold in the beaten egg whites, then pour into a small mold which has been lightly buttered.

Set the mold in a bowl of ice cubes and refrigerate until set, 4 to 5 hours.

Dunk the bottom half of the mold in hot water and the Marquise will slip out very easily.

Cut into wedges to serve.