Mix a tablespoonful of butter and one of flour; mix over the fire, with a cup of cold water, stirring all the time. When this boils, take a quarter of a pound of fresh butter, if for a number of guests, and stir in the butter quickly, adding a cup of cold water by degrees, to keep the butter from oiling; finish with the juice of a lemon, and strain. It must be served hot, and made only a few moments before it is wanted. It gets oily if kept long. Add a spoonful of chopped parsley.