Saute onions and peppers in butter. Prepare stuffing mix according to package. Combine sauteed vegetables, stuffing mixture, soup, mushrooms, seasoning and crab meat in a large bowl and mix well. Pour into a 13-by-9-inch Pyrex baking dish. Bake at 375 degrees for 15 minutes. Remove from oven and top with grated cheese (as much or as little as you want) and return to oven for 10-15 minutes.