A classic in Grandma's day.
- Peel and cut potatoes into slices about 1/8 inch thick. Immediately place in cold water to cover. Melt 1/4 cup margarine in medium saucepan, blend in flour. Gradually stir in milk. Cook over medium heat, stirring constantly, until mixture comes to a boil; boil and stir 1 minute. Stir in salt and pepper. Drain potatoes thoroughly. Layer potatoes, onions, ham and white sauce alternately in greased 3-quart casserole. Combine 1 tablespoon margarine and bread crumbs; sprinkle over potatoes. Bake, covered, in a preheated 325 F oven 45 minutes; uncover, bake until potatoes test done when pierced with fork (35-45 minutes longer).