1/2 lb. celery root, peeled and cut into 1/4 cubes (1 C.)
4 T. olive oil
1 medium onion, coarsely chopped
1 medium leek, white part only, cleaned and cut into 1/4 inch slices (1 cup)
2 shallots, coarsely chopped
1 garlic clove, mashed with salt and freshly ground pepper
1 T. salt
Freshly ground black pepper
8 C. chicken broth or vegetable broth
2 C. loosely packed watercress, stems removed
1 T. Dijon mustard
1 1/2 T. red wine vinegar
Heavy cream for decoration (optional)
1 T. chopped celery leaves (optional)
Cover the lentils with a generous amount of water in a 6-quart heavy bottomed
pot. Bring to a boil and keep a steady boil for 15 minutes. Drain and set aside
Heat the olive oil in the soup pot; add the celery root, onion, leek, shallots
and garlic. Cover and braise over medium heat for 10 minutes.
Add lentils to the vegetable mixture. Pour in the broth, season with salt and
pepper and bring to a boil. Reduce the heat, and cook at a gentle boil,
partially covered, for 1 hour. During the last 5 minutes of cooking, add the
watercress.
Puree the soup in batches in a blender until very smooth. Add more broth if the
soup is too thick. Whisk in the mustard and vinegar.
Just before serving, reheat the soup, taste and correct seasoning with more salt
and pepper. Ladle the soup into hot soup bowls or plates. Dribble the soup with
heavy cream and sprinkle with chopped celery leaves if you wish.
