Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/4  pound         butter
   1      teaspoon      arrowroot
   5      tablespoons   scalded milk -- warm
   1      pinch         salt
   2                    egg yolks
   2      tablespoons   lemon juice
   1      pinch         freshly ground pepper

Preparation:

In top of double boiler, combine 1 tablespoon butter, arrowroot, milk, salt, and egg yolks. Stir with wire whip until well mixed. Place top over boiling water and whip until mixture thickens. Remove top of double boiler and gradually add remaining butter cut into small pieces, whipping constantly, until smooth and well blended. Correct seasoning. Add lemon juice and pepper. Good with white-meat fish or boiled vegetables. Recipe Source: THE ART OF FRENCH COOKING by Fernande Garvin