This section is from the book "The Memorandum Cookery Book", by Countess Morphy. Also available from Amazon: The Memorandum Cookery Book.
I have never been able to understand why people consider the making of a mayonnaise sauce so difficult, nor why they think it is " too much trouble " (I should, by the way, like to make the use of that sentence " too much trouble " a punishable offence, especially when used about cooking). It usually takes me from 8 to 10 minutes to make a very stiff mayonnaise with 2 eggs— and who can begrudge that time when the result is so excellent ?
2 eggs, salad oil, vinegar, salt and pepper.
Put the yolks of 2 eggs in a basin, add 1/2 a teaspoon of salt and 1/2 of pepper (a little mustard powder can also be added), mix well with a wooden spoon, add 2 teaspoons of vinegar, stir well. Now start adding the oil drop by drop at first and turning steadily in the same direction. When the mayonnaise begins to thicken, a steady thin stream of oil can be poured in, but not more than the eggs can absorb. When the mayonnaise is very thick, add a little vinegar, drop by drop—this is the pitfall for most amateurs, for if too much vinegar is added or too much put in at a time, the mayonnaise will curdle. Keep in a cold place till required.