Cook the lentils in plenty of boiling water for about 45 minutes. Peel and wash carrots and celery and cut into cubes or slices. Peel and finely dice the onion. Heat 1 tablespoon of oil in a saucepan.
Sauté the vegetables in it. Add stock, bring to the boil, add noodles and simmer for about 10 minutes. Press the sausage meat out of the skin as a dumpling. Heat 1 tablespoon of oil in a pan. Brown the meatballs all around.
Pour the lentils onto a sieve, drain. Add the lentils and dumplings to the noodles 5 minutes before the end of cooking time. Wash parsley, dab dry and cut into strips. Season soup again.