Pre-heat oven to 190°C (170°C fan-forced).
Cook pasta in a large pot of boiling water. Drain well.
Meanwhile; combine bread, carrot, parsley and seasoning in a food processor and pulse until a fine mixture is achieved. Add to the beef in a large mixing bowl and mix with hands until well combined. Roll tablespoon measures into balls and set aside.
Heat half the oil in frying pan and cook meatballs in batches over a medium heat for 6-8 minutes until golden all over. Set aside.
Add remaining oil to pan with the onion and garlic. Cook for 2-3 minutes until tender. Stir in tomato paste and cook a further minute.
Pour in tomatoes, passata and stock. Bring to a simmer, add meatballs back to pan with basil and balsamic. Cook a further 5-6 minutes.
Spread pasta into the base of a deep 10 cup capacity oven-proof dish. Spoon meatball mixture over the top and arrange mozzarella slices sprinkled with parmesan on top. Bake for 25 minutes until cheese is melted.