Preheat the oven to 400 degrees. Butter a one quart souffle' dish or four eight-ounce souffle' dishes. Melt the chocolate in a double boiler and add the sugar and vanilla. Allow the mixture to cool. Whisk the egg yolks until they are pale yellow. Gradually stir them in the warm (but not hot) chocolate. The recipe can be prepared ahead to this point. Beat the egg whites until they stand up in glossy peaks. Stir one third of the egg whites into the chocolate mixture, then gradually fold in the rest. Bake souffle' in the center of the oven for about 25 minutes for a large souffle' or about 10 minutes for the smaller ones. Remove from the oven and dust with the confectioners sugar and serve. Pass whipped cream seperately.
