Three eggs, one table-spoonful each of sugar, oil and salt a scant table-spoonful of mustard, a cupful of milk and one of vinegar. Stir oil, salt, mustard and sugar in a bowl until perfectly smooth. Add the eggs, and beat well; then add the vinegar, and finally the milk. Place the bowl in a basin of boiling water, and stir the dressing until it thickens like soft custard. The time of cooking depends upon the thickness of the bowl. If a common white bowl is used, and it is placed in water that is boiling at the time and is kept constantly boiling, from eight to ten minutes will suffice; but if the bowl is very thick, from twelve to fifteen minutes will be needed. The dressing will keep two weeks if bottled tightly and put in a cool place.
Source:
Miss Parloa's New Cook Book
