Italian Beans Casserole

2 pounds Italian sausage, hot and/or sweet
2 onions, chopped
1 large can tomato puree
1 can tomato paste
2 cans red kidney beans
1/3 cup Parmesan cheese

Crumble sausage and saute with onions until done, but not crisp. Add remaining ingredients; simmer at least 20 minutes. Transfer to casserole, sprinkle with more cheese. Bake at 350 to heat.