* and drained ** in one piece *** use white parts of leeks only, cleaned and washed **** cook and drain sausage links in large kettle with 6 cups water. Cook slowly, covered, 1 1/2 hours, until tender.
Put bacon, carrots, celery root, leeks, onions, thyme, salt, and pepper in another kettle. Cover with water. Cook slowly, covered, 40 minutes until vegetables and bacon are tender. Take out bacon; slice and keep warm. Remove vegetables and add to cooked split peas with as much as the broth in which the vegetables were cooked as desired to thin the soup. Reheat, if necessary. Ladle soup, including vegetables, into wide soup plates and serve sliced bacon and the cooked sausage links separately on a platter.
Serve with dark bread, mustard, and beer.
Serves 6 to 8.