Julia Child's Classic Potato and Leek Soup

3-4 cups of diced peeled potatoes (1 lb.)
3 cups thinly sliced leeks, including the tender greens
2 quarts water
1 Tablespoon salt
6 tablespoons heavy cream or 3 tablespoons softened butter *
3 tablespoons minced chives or parsley *

* optional

Simmer vegetables, salt, and water together, partially covered for 40-50 minutes in a 3-4 quart saucepan. Mash the vegetables into the soup with a fork or pass through a food mill.  Adjust salt and pepper. You can stop at this point.

When ready to serve, bring soup back to simmering. Remove from heat and, stir in the cream or butter and top with chopped chives or parsley if you please. Makes 2 quarts of soup for 6-8 servings.