Peel and chop the onions. Clean and wash the soup vegetables. Cut parsley root into slices, leek into rings. Finely dice carrots and celery. Peel, wash and chop potatoes.
Wash bones. Put bones, soup vegetables, onions, potatoes, bacon, peas, peppercorns and bay leaves in a large pot. Add 3 litres of water, bring to the boil and cook covered for about 3 hours.
Stir several times. Wash parsley, shake dry and chop finely. Then season the soup with salt, pepper, sugar and seasoning (e.g. from Maggi®). Heat the sausages in warm water. Then add to the soup.
Arrange the soup sprinkled with parsley in a terrine.