One-half teaspoonful of mustard, one-half teaspoonful of sugar, one
teaspoonful of salt and a dash of cayenne pepper; then add two raw egg
yolks, beat well and stir in a teaspoonful of strong vinegar; add very
carefully, drop by drop, a scant three-quarters of a cup of best olive
oil, and as it thickens half a teaspoonful of vinegar. This recipe never
fails, if the directions are carefully followed. The eggs and oil should
be kept in the refrigerator and be ice cold. Lemon juice may be used,
instead of vinegar, if preferred.