Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
     1/4  cup           dry white wine
     1/4  cup           white vinegar
   2                    shallots -- chopped
   4                    peppercorns -- crushed
   3                    egg yolks
     3/4  cup           butter -- (1 1/2 sticks)
     1/2  teaspoon      salt
     1/2  teaspoon      dried tarragon leaves
     1/2  teaspoon      finely chopped parsley

Preparation:

In small, heavy saucepan, combine wine, vinegar, shallots, and peppercorns. Cook over brisk flame until liquid is reduced to approximately 2 tablespoons. In top of double boiler, combine egg yolks, 1 tablespoon butter, salt, and tarragon. Strain liquid from saucepan through a fine sieve into top of double boiler. Mix well. Place top over hot (but not boiling) water and cook, whipping constantly, until creamy. Gradually add remaining butter cut into small pieces, whipping constantly until smooth and well blended. Add parsley. Serve warm. (Bearnaise cannot be served hot because heating would cause it to curdle.) It should be the consistency of thick mayonnaise. Comments: In France, sauce Bearnaise is seldom made at home. French housewives are reluctant to make it because it is one of the hardest things to make successfully. Many dishes which seem difficult, such as soufflé, omelet, or puff paste, require only reasonable attention. Bearnaise is so sensitive that it will curdle at the drop of a piece of butter. If you do make it, remember: It should be whisked briskly all the time; the pan should not be heated to boiling point; the butter should be added in small pieces and thoroughly blended each time before adding another piece. Recipe Source: THE ART OF FRENCH COOKING by Fernande Garvin