IRISH POTATO CASSEROLE

5 potatoes, thinly sliced
1 large onion, thinly sliced
salt and pepper, to taste
1 can cream of mushroom soup
3/4 cup milk
2 tablespoons margarine, melted
1/2 cup grated Cheddar cheese
Preheat oven to 350°.
Alternate potatoes and onions in layers in 2-quart greased casserole dish.
Add salt and pepper to each layer.
Mix soup, milk and melted margarine and pour over. Bake in 350° oven until done (40 to 50 minutes). Then top with cheese and bake until cheese melts.