Sauce Béarnaise
5 yolks of eggs
2 ozs. butter
1 table-spoon chopped tarragon
1 dessert-spoon vinegar
Put the yolks in a sauce-pan, in a bain marie, and stir into them one ounce of butter. As soon as the eggs begin to thicken, take off the fire. Add another ounce of butter, the tarragon and vinegar. This sauce should be of the consistency of a mayonnaise. Serve with roast meats.