Place the egg yolks in the bowl of the food processor and add the vinegar and mustard. Season with salt, to taste. Turn the machine on and VERY slowly start to drizzle in the oil. Drip, drip, drip until the mixture starts to look like mayonnaise, then a slow steady stream of oil can be added.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.