Sauce Bernaise
Into 1 tablespoon of reduced vinegar beat slowly the yolks of 4 eggs to which has been added 2 tablespoons of cold water, and when well mixed hold in a small saucepan above a slow fire; put in a small bit of butter, and when melted stir in another, and so continue until 1½ tablespoons have been used. When the sauce is smooth and creamy, season with salt and pepper or paprika, and add ½ teaspoon of tarragon vinegar, or 1 teaspoon of minced tarragon leaves. The sauce cannot be served very hot or it will curdle. It may be served cold also.