Scalloped Potatoes and Ham

From Betty Crocker Easy Casserole & One Dish Meals Aug/Sept 1997

6 medium boiling or baking potatoes (2 pounds) peeled
3 Tbsp margarine or butter
1 small onion, finely chopped
3 Tbsp Gold Medal all-purpose flour
1 tsp salt
1/4 tsp pepper
2 1/2 C milk
1 1/2 C diced fully cooked ham
1 Tbsp margarine or butter

Heat oven to 350. Grease 2-quart casserole.
Cut potatoes into enough thin slices to measure about 4 cups.
Melt 3 tablespoons margarine or butter in saucepan over medium heat. Cook onion in margarine about 2 minutes, stirring occasionally, until tender. Stir in flour, salt and pepper. Cook, stirring constantly, until smooth and bubbly; remove from heat.
Stir milk into sauce. Heat to boiling, stirring constantly. Boil and stir 1 minute. Stir in ham.
Spread potatoes in casserole. Pour sauce over potatoes. Dot with 1 tablespoon margarine.
Cover and bake 30 minutes. Uncover and bake 1 hour to 1 hour 10 minutes longer or until potatoes are tender. Let stand 5-10 minutes before serving.