Mix potatoes and cabbage together in large bowl. Season to taste with salt and pepper. Fry bacon in large skillet until crisp. Put bacon aside and fry onion in same skillet. Add half of the butter to the same skillet and stir in potato and cabbage mixture. Mix and heat through. Transfer to a buttered oven baking dish. Sprinkle with bread crumbs and dot with rest of the butter. Place in 425 degree oven and bake until lightly browned, about 15 minutes. Crumble crisp bacon and sprinkle on top.