1.Preheat oven to 220°C/200°C fan forced.
2.Place bread in a large bowl; cover with milk. Mix with hands to break up. Add mince to bowl with half the onion and garlic. Add the egg, oregano and 1/3 cup of the parmesan. Season. Mix well with hands. Divide mixture into 24 portions. Roll each portion into a ball.
3.Heat half the oil in a 26x34cm (base measurement) flameproof roasting pan over moderate heat. Add meatballs; cook and turn for 5-8 minutes or until browned. Transfer to a heatproof plate.
4.Add remaining oil, onion and garlic to pan; cook and stir for 5 minutes or until soft. Add passata, tomatoes and stock; bring to the boil. Season. Return meatballs to pan; turn to coat in sauce. Sprinkle with basil, bocconcini and remaining parmesan. Bake for 12-15 minutes or until browned. Serve with mash.
Use pork and veal mince, beef mince or a combination of your favourites.Note