Grandma Margaret's Lima Bean Casserole

2 packages frozen limas

1 medium onion, chopped

1 bell pepper, chopped

1 stick butter

2 cans mushroom soup

1 cup grated cheddar cheese

Cook frozen lima beans until tender and drain.  Brown bell pepper and onion in butter in a 350° oven.  Add beans and mushroom soup.  Cook 30 minutes at 350°.  Top with cheese and bake until bubbly.