Au Gratin Potatoes
["14 medium potatoes", "salt and pepper", "onion (if desired)", "2 sticks margarine", "1 large jar Cheez Whiz", "1 small box Velveeta cheese", "2 c. milk"]
["Boil and slice potatoes.", "Heat in pan the last four ingredients until melted.", "Pour over potatoes.", "Bake at 350\u00b0 for 1 hour."]
["potatoes", "salt", "onion", "margarine", "Velveeta cheese", "milk"]