Cabbage Casserole

1 head cabbage, shredded ( about 12 cups)
1 can cream of mushroom soup, undiluted
1 onion, chopped
5 tablespoons butter or 5 tablespoons margarine, divided
6 ounces American cheese, cubed
1/4 cup dry breadcrumbs
salt (optional)
pepper (optional)
Directions
Cook cabbage in salted water until tender; drain thoroughly.
In a large skillet, sauté onion in 4 Tbsp.
of butter until tender.
Add soup and cheese, heat and stir until melted.
Stir in cabbage (salt& pepper if desired).
Transfer to an un-greased 2-quart baking dish.
In a small skillet, melt remaining 1 Tbsp.
butter; stir in breadcrumbs.
Brown lightly.
Remove from heat and sprinkle over casserole.
Bake uncovered at 350ºF.
for 20-30 minutes, or until heated through