In a medium bowl, combine the lemon juice, egg yolk, mustard, and salt. Slowly add approximately a third of the oil, drop by drop, whisking vigorously. When the mayonnaise begins to set, add the remaining oil in a stream, beating continuously. Season with pepper.
In a food processor or blender
In the container of the device, place the lemon juice or vinegar, whole egg, mustard, and salt. Cover and blend for a few seconds. Adjust the speed at low rpm. While the device is running, add the oil through the opening in the lid, in a continuous stream (the mayonnaise will set quickly, in less than a minute). If necessary, stop the machine and use a spatula to clean the side of the container or to push the ingredients into the blades.
Find a wealth of ideas to flavour your mayonnaise on ricardocuisine.com.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.