Mix mince, egg, breadcrumbs, 1 tablespoon parsley, grated onion, salt and pepper together. Form big meatballs.
Cut out stork of cabbage, cutting out big circle at the bottom going small towards the inside. Bring large pot of water to the boil. Put cabbage in water with the open end in the water first. Submerge and leave for about 3 minutes. Remove from water. Remove leaves one by one. Cut out bottom hard starks of leaves.
Put one meatball in each leave and cover completely. Pack these in casserole dish. Heat oil, fry onions and garlic till opaque. Add stock, carrots, celery, leeks, potatoes, parsley, pepper & salt. Cook through. Pour over cabbage meatballs.
Cover and cook on 180°C (356°F) for 1 and a half hour. Serve with wild rice.