Bearnaise Sauce - cooking recipe

Ingredients

1/4 cup white wine vinegar or 1/4 cup tarragon vinegar
1/4 cup white wine or 1/4 cup vermouth
2 teaspoons shallots, minced
1 tablespoon fresh tarragon, minced
salt and pepper
2 egg yolks
1/4 lb butter
1/2 lemon, juice of
1 tablespoon parsley, minced (or Chervil)

Preparation

In a small saucepan, bring vinegar, wine, shallots, tarragon, salt and pepper to a boil and reduce to about 2 tablespoons.
Cool slightly.
Beat in yolks until smooth.
Put mixture into a small stainless steel bowl and place in a skillet with about 1 inch of simmering water in it.
Whisk sauce until it begins to thicken.
Beat in butter, bit by bit.
Before serving, add a few drops of lemon juice and parsley.