Clean and wash the celery and chard and cut into strips. Peel and wash the carrots and cut them into diagonal slices. Clean and wash the spring onions and cut the thick lower end into slices and the green into wide strips. Heat the stock and cook the meatballs in it at low heat for about 12 minutes. Add celery and carrots.
After about 5 minutes add chard and spring onions to the stew. Wash the tomatoes. Cut out the stem base. Cut the tomatoes into slices and add them to the stew shortly before the end of the cooking time. Season stew with salt and pepper and serve hot