Easy Scalloped Potatoes
["1/4 c. margarine", "3 Tbsp. all-purpose flour", "1/2 tsp. salt", "dash of pepper", "2 c. milk", "4 c. thinly sliced potatoes", "1 small onion, thinly sliced and separated into rings", "dash of paprika", "1/2 c. shredded Cheddar cheese"]
["Butter 1 1/2-quart casserole.", "For sauce, in heavy saucepan, over medium heat, melt butter.", "Stir in flour, salt and pepper until smooth.", "Gradually stir in milk; cook until mixture boils, stirring constantly."]
["margarine", "flour", "salt", "pepper", "milk", "potatoes", "onion", "paprika", "Cheddar cheese"]