Preheat oven to 180C/160C fan-forced.
Pour passata, stock and vinegar into a 3.5L capacity baking dish. Mix to combine and season with salt and pepper.
Combine the mince, rice, milk, egg, onion, herbs and seasoning in a bowl. Using ½ cup mixture at a time, roll into balls and add to sauce.
Cover and bake for 1 hour or until meatballs are cooked through. Stand, covered, for 10 to 15 minutes. Serve meatballs, sprinkled with parsley.
