Beef Baked with Onions and Potatoes

1 lb. lean ground beef, browned and drained
1 onion, chopped
4 Irg. potatoes, peeled and sliced
1 10 1/2 oz. can vegetable beef soup

Preheat oven to 375°. Brown ground beef and onions, then drain. Place potato slices in lightly greased casserole. Spread ground beef and onions over potatoes. Pour soup over top. Cover and bake for 45 minutes, then uncover and bake for another 25 minutes (for a total of 70 minutes).