This section is from the book "The American Woman's Cook Book", by Ruth Berolzheimer. Also available from Amazon: The Domestic Arts Edition of the American Woman's Cook Book.
1 tablespoon lemon juice
Place egg yolks with 1/3 of the butter in top of a double boiler. Keep water in bottom of boiler hot but not boiling. Stir eggs and butter constantly; when butter melts add another portion and as it melts and the mixture begins to thicken add remaining butter. Keep stirring all the time. As soon as mixture is thick, remove from heat and add seasonings. The sauce is delicious served over vegetables. Should sauce separate, beat in 2 tablespoons boiling water, drop by drop. Makes 1 cup sauce.
Increase lemon juice to 1 1/2 tablespoons.
With Water - Cream butter, add egg yolks 1 at a time, blending each one in thoroughly. Add remaining ingredients and beat. Just before serving add 1/2 cup boiling water gradually, beating constantly. Cook over hot water, stirring constantly until thickened. Serve at once.
With Anchovy - Season sauce with anchovy paste.
With Sherry - Just before serving sauce, add 2 tablespoons sherry, drop by drop, beating constantly.