One-quarter of a cup of strong cider vinegar, one cup and a quarter of
water, one-half cup of butter, one teaspoonful of mustard, one
teaspoonful of salt, one tablespoonful, slightly heaping, of corn
starch, one teaspoonful of sugar, a dash of cayenne pepper and the yolks
of four eggs. Put the vinegar and water in a saucepan and when it boils
add the butter. Beat the yolks of eggs and the other ingredients
together with an egg-beater, making it quite foamy and light; pour the
boiling vinegar and water upon this mixture, which will partially
thicken. The bowl in which it is mixed should be placed in a pan of hot
water on the stove, beating it all the time with the egg-beater. Just
before it reaches the boiling point remove and turn it out into a cold
bowl, beating hard for a few minutes. When perfectly cold pour it into a
glass jar, fasten down the top and keep in refrigerator.