- Preheat oven 220°C.
- Tear bread into small pieces and combine with the milk in a large bowl. Press the bread down into the milk to fully submerse and soak into the bread. Combine all of the meatball ingredients in the bowl with the soaked bread, and mix well with your hands. Roll about two tablespoons worth into one meatball and form into a ball. Repeat with remaining meatball mix.
- Heat one tablespoon of olive oil in a large non stick pan over medium high heat. Brown the meatballs on all sides until golden. Transfer to a warm plate.
- Heat the remaining tablespoon of olive oil in the pan. Fry the onion until transparent, while stirring occasionally. Add in the garlic and sauté for 1 minute until fragrant. Stir through the purée, water, tomato paste, herbs, chilli flakes, salt and pepper. Mix together well with a wooden spoon; bring to a simmer. Reduce heat down to low.
- Transfer the meatballs back into the sauce, along with any juices released from the meatballs on the plate. Allow the meatballs to cook for a further 20 minutes, covered and still on low heat, while turning and stirring the sauce occasionally, until meatballs are cooked through. Top with the mozzarella cheese; transfer to the oven and bake until the cheese has melted and is bubbling. Garnish with the freshly chopped parsley and serve over pasta or with toasted ciabatta.