Grate raw potatoes ( and knuckles raw ) and mix with the cooked mashed potatoes. Add salt, pepper and flour. Beat egg and add to mixture with just enough milk to make a batter that will drop from a spoon. Drop by tablespoonfuls onto a hot griddle or frying pan. Cook over a moderate heat for 3-4 minutes on each side. Serve with a tart apple sauce: or as part of an Ulster Fry, with fried bacon, fried sausage, fried eggs, fried black pudding, fried bread, fried soda bread.
Other possible variations: Add minced red onion or green onions, garlic or leftover shredded corned beef