This is a very good sauce to use either hot or cold with meats and fish. It is very like Mayonnaise.
Beat the yolks; add the oil and water; stand the bowl in boiling water and stir until the eggs thicken; remove and add salt, pepper, and vinegar. It should be creamy and of the consistency of Mayonnaise. A few chopped capers, olives, and gherkins make it a good Tartare sauce; and a little tomato puree will make it a red Mayonnaise to use with cold boiled fish.