Put the milk in the double-boiler, and place on the fire. Beat the butter to a soft cream, and beat the flour into it. Gradually pour the hot milk on this, stirring all the time. Return to the fire and cook for six minutes.
Put the shaved chocolate, sugar, and two tablespoonfuls of water in a small pan over a hot fire, and stir until smooth and glossy. Stir this into the mixture in the double-boiler.
Take from the fire and add the yolks of the eggs, well beaten; then set away to cool. When cool add the whites of the eggs, beaten to a stiff froth.
Pour the batter into a well-buttered earthen dish that will hold about a quart, and cook in a moderate oven for twenty-two minutes. Serve immediately with vanilla cream sauce