In a large cast iron skillet satue onions and pepper in butter until onion is transparent. Add milk, and flour stirring constantly, cook until thickened. Add Crab meat, seasoning, and hot sauce. Place half the mix in a greased casserole dish; sprinkle half the cheese on top and cover with bread crumbs, add the rest of the mix, sprinkle the rest of the cheese and bread crumbs over the top and bake at 350 degrees for 20 minutes. Don't burn the topping.