Preheat oven to 180C.
To make the meatballs add all the ingredients except for the cheese and oil to a large bowl,and using your hands,massage to combine. Divide mixture into six,and form into flat oval shapes. Place a piece of mozzarella in the centre of each oval,fold to enclose and roll to seal and form a ball just smaller than a tennis ball. Place the six meatballs on a tray lined with baking paper,cover and refrigerate for 30 minutes.
While the meatballs are resting,start the soup. Add the olive oil,onion,garlic,zucchini and celery to a large saucepan over medium heat. Cook for 15 minutes or until the onion and garlic is soft. Add the tomato passata,wine and stock,reduce the heat to low and simmer for 20 minutes.
While the soup is simmering,cook the meatballs. Heat the olive oil in a large oven-proof frying pan over medium-high heat,add the meatballs and brown all over (4 to 5 minutes). Place the frying pan in the preheated oven until the meatballs are cooked through (15 minutes).
Just before serving,add the cooked pasta,chickpeas,white beans and silverbeet to the soup to warm through (about five minutes). Ladle the soup into bowls and top each bowl with a meatball. Scatter with herbs and chilli flakes and serve.
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