To make the meatballs, combine chicken, breadcrumbs, half of the parsley and egg in a bowl. Season with salt and pepper. Shape mixture into 20 small balls (about the size of a 50c piece). Place onto a plate, cover and refrigerate
Meanwhile, heat oil in a large pan over medium heat. Add onion and cook, stirring often, for 3 minutes until just tender. Add garlic, celery, carrots and potato. Cook, stirring often, for 5 minutes
Add stock and cabbage, cover and bring to the boil. Reduce heat, cover and simmer over medium-low heat for 45 minutes. Add chicken meatballs and remaining parsley and simmer for 8-10 minutes until chicken meatballs are just cooked through. Season with salt and pepper, sprinkle with parmesan. Ladle into bowls and divide the meatballs evenly.