Dutch Style Green Pea Soup

2 lb. fresh ham hocks
3-4 qt. water
1 lb. pre-soaked split green peas
8 leeks, finely chopped
1 celery root, peeled and diced
3 c. chopped celery leaves
1 bay leaf
1/2 to 3/4 tsp. thyme, rubbed
1/8 tsp. dry mustard
2 tsp. salt
1 tsp. pepper
2-3 c. chicken broth (optional)

The day before serving, place the ham hock and water in a large soup kettle. Bring to a boil and then simmer until meat is very tender (2 1/2 hours). Cool and skim off fat. Remove meat and add to liquid the remaining ingredients except meat and chicken broth. Dice meat and return to kettle. Simmer 3 hours. If soup is too thick, chicken broth can be added. Refrigerate; serve the next day as this soup is best after the first day and is excellent garnished with Parmesan and croutons. Yields 8-10.