Serves 4 to 6-
6 cups vegetable broth or water
6 medium leeks, white parts plus an inch of the greens, sliced into ¼ inch rounds
2 tablespoons butter
1 bay leaf
4 lemon thyme or regular thyme sprigs
1 ½ teaspoons sea salt
1 tablespoon flour
1/3 cup milk or cream
freshly milled pepper
3 tablespoons chopped herbs: chervil, basil, dill, or tarragon; or 1 tablespoon chopped rosemary or lovage
Separate the sliced leeks into rings and soak them in a bowl of water for 5 minutes. Lift them out, letting any sand fall to the bottom. You should have about 4 cups; if not, make up the difference with green or white onions.
Melt the butter in a soup pot and add the leeks, bay leaf, thyme, salt, and 1 cup of stock or water. Cover the pan and stew over medium heat until the leeks are tender, about 10 minutes. Stir in the flour, then pour in the remaining 5 cups of stock or water. Bring to a boil, then lower the heat and simmer, covered, for 20 minutes.
Remove the bay leaf and thyme, puree the soup, then return to the pot. Add the milk and bring to a simmer. Taste for salt and season with pepper. Stir in the fresh herbs and serve.
From The NEW VEGETRIAN COOKING for EVERYONE by Deborah Madison, Ten Speed Press, Berkley, California, 2014, pages 185-186.