In a large saucepan put 4 cups of fresh peas, 6 tablespoons of butter, 1 finely minced onion, a tender head of garden lettuce cut into julienne strips, about 15 leaves of fresh spinach, 4 sprigs parsley, a few sprigs of chervil if you have it, 2 teaspoons of sugar, 1/2 teaspoon salt, and 1 3/4 cups water. Cover the saucepan, bring the soup to a boil, and cook it over a moderate fire until the peas are tender. Meanwhile, boil 1 cup of fresh peas, in a separate pan, to add to the soup later.
Pass the soup through a strainer, or a vegetable mill, pressing the vegetables through with the liquid. Return the soup to the saucepan, add 3 cups of chicken stock, stir well, and simmer over a low fire for about 15 minutes. Then add the extra cup of peas, drained, and 1/4 cup cooked white meat of chicken, cut into very fine julienne strips.
Mix 3 egg yolks with 1 1/2 cups of light cream and add this gradually to the soup, stirring constantly. Continue cooking until the soup thickens to a creamy consistency, but do not let it boil.
The next time you boil a chicken for a fricassee, reserve some of the white meat and stock for this delectable soup. (Or you may use leftover roast chicken and canned chicken broth.)
Recipe courtesy of Samuel Chamberlain's Clementine in the Kitchen (Random House, 2001)