1 ½ cups vegetable oil (or a combination of vegetable and olive oils)
Pinch ground white pepper
In the bowl of a food processor or blender, combine the egg yolks, water, and vinegar, and whirl just until the ingredients are combined. With the motor running, drizzle in the oil very slowly; if the oil is added too quickly, it will become a liquid dressing.
Transfer the egg mixture to the top of a double boiler and cook until a thermometer placed in the sauce registers 160°F. Stir in the white pepper. Store in the refrigerator for up to 5 days. Makes 2 1/2 cups.