Mix the beef with the egg, the breadcrumbs, the nutmeg, the oregano, 1 clove garlic and pepper and salt to taste and make small balls of this mixture. Fry them in olive oil until brown on all sides. Add the onion and the remaining clove of garlic and fry two minutes more. Add the tomatoes and the stock, bring this to the boil and simmer for 20 minutes. Sprinkle with parsley.