Mash the yolks of 4 hard boiled eggs and add to them 4 tablespoonfuls of
butter and one tablespoonful of flour. Mix well together, then add
one teaspoonful of salt, one of sugar, one of mustard, one-half cup of water and one-half cup of vinegar. Stir it over the fire until it thickens, and when cold it is ready to use