Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
   2      tablespoons   butter
   2      tablespoons   flour
   1      cup           bottled clam juice
   1      cup           water
   2      tablespoons   chopped fresh mushrooms
                        (or canned sliced mushrooms)
   1      pinch         grated nutmeg
   1      pinch         thyme
   1      small         bay leaf
     1/2  teaspoon      salt
     1/4  teaspoon      white pepper
     1/8  cup           heavy cream
   2                    egg yolks

Preparation:

Heat butter in heavy saucepan. Stir in flour. Add clam juice and water and cook, stirring constantly, until smooth. Add mushrooms, nutmeg, bay leaf, thyme, salt, and pepper. Cook over low flame, stirring occasionally, for 30 minutes. Add cream. Stir in yolks. Heat but do not allow to boil. Serve hot. Recipe Source: THE ART OF FRENCH COOKING by Fernande Garvin