Cook squash and onion together until tender, drain off water. Beat egg and add flour, half of the cheese, salt, pepper, mustard, powdered milk and margarine. Add squash and pour into Pam coated pie pan. Bake in a 350 degree oven for 25 m inutes. Remove and sprinkle with the remaining cheese. Bake for 5 minutes more. Makes 4 servings. Recipe from "One Million Recipes CD" busted by Judy R.