1 can cream of celery or mushroom soup
3/4 c. milk
4 c. thinly sliced potatoes
1 medium thinly sliced onion
1 c. grated Cheddar cheese
1 tbsp. butter

Preheat oven to 375°F.

Grease quart casserole. Blend soup, milk, salt and pepper. Put layer of potatoes, onion and cheese. Pour soup mixture over top. Dot with butter. Cover and bake 1 hour. Remove, cover and bake until done, about 15 minutes longer.