Cut steak into thin pieces, about 4 ½ by 2 inches. Score, sprinkle with salt and pepper. Combine bread crumbs, egg, onion, 4 tablespoons melted butter, salt and pepper. Spread the dressing on each piece of meat, roll up and fasten with skewer or toothpick. Roll in flour and brown in remaining butter. Add 2 cups of water (meat stock, if you have it) and simmer 1 ½ hours. Remove toothpicks. Pour gravy over meat. Garnish with chopped parsley and mashed potatoes.