One more bargain from Waitrose - well actually several more - there could be a few meatball recipes soon, due to bumper bargain meatball swoop. Chopped onion and celery, sauteed in olive oil with garlic, added chopped courgette and chili. Stirred in meatballs, a tin of chopped tomatoes some stock and a squirt of tomato puree. Boil spaghetti. Serve with grated parmesan and ground black pepper.