Pound the yolks of 2 hard-boiled eggs to a paste with a drop of vinegar. Stir in a raw yolk, a teaspoonful of French mustard, salt, pepper. Add olive oil (about 1/4 pint) as for a mayonnaise. Flavour with chopped tarragon, chives and capers, allowing about one teaspoonful of each.
This makes a sauce of a creamier consistency and less rich than a mayonnaise.