Melt 2 tablespoons butter. Add 2 tablespoons flour. Blend. Add 1 cup milk and stir until smooth and creamy. Add 5 well beaten egg yolks, salt, pepper and 1/2 teaspoon baking powder. Fold in 5 stiffly beaten egg whites. Melt 2 or 3 tablespoons butter in casserole. Add egg mixture. Bake in 350 degree oven until firm and delicately browned.