Tuscan meatball soup

Ingredients

• 1 kilogram chicken wing tips
• 1 kilogram chicken necks
• 1/4 cup olive oil
• 1 kilogram pork and veal sausages
• 1 celery heart, chopped
• 2 large carrots, chopped
• 1/2 bunch parsley, leaves and stems separated, stems chopped
• 1 bunch silverbeet, leaves shredded, stems chopped
• 4 litres (16 cups) water
• 2 onions, diced
• 1 leek, trimmed, chopped
• 4 cloves garlic, crushed
• 1 cup risoni
• grated parmesan, to serve