Scalloped Potatoes
["2 Tbsp. liquid margarine", "1 Tbsp. flour", "1 1/2 c. skim milk", "4 potatoes, peeled and sliced", "1 onion, sliced", "salt and pepper"]
["Melt margarine; stir in flour.", "Add milk slowly, stirring constantly.", "Cook and stir over low heat until thickened.", "Season to taste with salt and pepper.", "Place potatoes and onion in baking dish; pour in sauce.", "Bake for about 45 minutes at 350\u00b0."]
["liquid margarine", "flour", "milk", "potatoes", "onion", "salt"]