Directions:

Preheat oven to 350 °.
Beat egg whites until fluffy and able to hold a peak. Beat yolks until light colored and slightly thickened.
Add flour, nutmeg, salt and pepper to the melted butter in a saucepan. Heat and stir until the mixture thickens. (This will happen very quickly.) Add the 1 cup milk, continue to heat and stir constantly. Add the mustard and the grated cheese. Continue stirring until the cheese has melted and the mixture is thickened and bubbly. Remove the pan from the heat and pour a third to half of the hot mixture into the beaten egg yolks stirring continuously. Pour the combined yolks and cheese sauce into the pan wiith the remaining cheese sauce, stir it in and return it to the burner and heat to bubbly stirring continuously. Remove from the heat as soon as it starts boiling. Slowly pour the hot mixture into the beaten egg whites, folding it gently into the egg whites as you pour with a spatula. DO NOT stir vigorously. You will see some patches of beaten egg white that appear not to be combined with the cheee sauce. Not to worry! Pour the mixture into an ovenproof bowl preferably with straight sides that has been buttered and floured at least hallf way up the sides. Take a tablespoon and 'cut' a circle around the top of the mixture an inch or 2 from the sides of the bowl. This will create a 'high hat' souffle as it bakes. Set the bowl in a shallow pan into which you have placed 1 inch of hot water. This coud be hot water from your tap. Place in the oven and bake for 50 min to 1 hr. It is done when the top is puffed and golden brown.