Potato-Sorrel Soup

(from ‘The Greens Cook Book’ (Greens Restaurant, San Francisco Marina)

The Stock

Water is fine for this soup.

The Soup

5 tablespoons butter

7 cups water

3 leeks, white parts only (about 8 ounces), cut into 1/4-inch rounds or strips

4 to 6 ounces sorrel leaves (about 8 cups), stems removed and roughly sliced or chopped

½ teaspoon salt

1 1/2 pounds red potatoes, quartered lengthwise and thinly sliced

Pepper

Sour cream or crème fraîche (optional, for garnish)

1 tablespoon chives (ciboulettes), thinly sliced, for garnish

Melt the butter in a soup pot with ½ cup of the water. Add the leeks, sorrel, and salt, and stew, covered, for 5 minutes over medium-low heat. Add the potatoes and cook another 10 minutes, stirring occasionally. Pour in the rest of the water and gradually bring it to a boil. Lower the heat and simmer until the potatoes are tender, about 30 minutes.

Taste the soup and add more salt if necessary. Serve the soup with a grinding of black pepper, a spoonful of sour cream or crème fraîche, if desired, and the chives.

Serves four to six.