Put the bread in a large bowl, moisten with the milk and leave to soak.
Heat half the oil in a frying pan over a medium heat. Add the spring onions or onion and garlic and cook for 5 minutes until soft and just beginning to brown.
Combine the minced beef with the moistened bread, the cooked onions and garlic and Parmesan, and season with nutmeg, salt and pepper. Work together with your hands until the mixture is well mixed and smooth. With clean, wet hands, roll the mixture into 28 even-sized balls.
Heat the remaining oil in a large, nonstick frying pan. Add the meatballs, in batches, and cook until browned all over. Transfer to a shallow ovenproof dish.
Add the wine and tomatoes to the pan and bring to the boil, scraping up any sediment from the base. Add the bay leaves, season with salt and pepper and boil rapidly for 5 minutes. Pour over the meatballs, cover with foil and bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 1 hour, or until tender. Serve with spaghetti, garnished with basil leaves.