To make the sauce: heat the oil in a large heavy based saucepan (that can go in the oven). On medium low heat, fry the onion, garlic, anchovies and chilli until soft. Add the white wine and cook off for 5 minutes. Now add the crushed tomatoes, the passata and bay leaves. Season with salt and pepper. Bring to the boil and then turn down to a low heat. Simmer for 30 minutes. Now add the basil.
Pre heat the oven to 200?C.
For the meatballs: Mix the veal and pork mince with ricotta, egg, parmesan, bread crumbs, parsley, thyme, tomato paste and the garlic. Season with salt and pepper. Combine well with your hands.
Form the mixture into large balls (size of a tennis ball). Pierce the meatball with the mozzarella and ensure you seal well with the meat. Place meatballs on to a tray and bake in the oven and cook for 15 to 20 minutes.
Once cooked, add the meatballs to the sauce, and place back into the oven and cook for another 35 minutes at 180?C.