Cheddar Scalloped Potatoes

1 can Campbell's Cheddar cheese soup
1/2 cup milk
Dash of pepper
4 cup thinly sliced potatoes
1 small onion, thinly sliced

Preheat oven to 375 degrees F.

Blend soup, milk and pepper in a mixing bowl. Arrange alternate layers of potatoes, onion and soup mixture in a buttered 1 1/2-quart casserole baking dish. Dot top with 1 tablespoon butter. Cover and bake for 1 hour. Uncover and bake 15 minutes more or until potatoes are done.