If you have a large food processor, use the smaller bowl attachment that came with your processor so that the bowl is not too large for the amount of mayonnaise this recipe makes.

Add egg to the small bowl of a food processor and process for 20 seconds. Add the mustard, vinegar, and salt. Process for another 20 seconds.

Scrape the sides and bottom of the bowl, turn the food processor on then begin to slowly add the oil in tiny drops until about a quarter of the oil has been added.

When you notice that the mixture is beginning to thicken and emulsify, continue to add it slowly, but increase to a very thin stream instead of drops of oil.

When all of the oil has been added, scrape the bottom and sides of the bowl and process for an extra 10 seconds. Taste for seasoning then add salt, lemon juice or extra vinegar to taste.

Add egg, mustard, vinegar, lemon juice (optional), and salt to a tall, narrow jar. Then, pour all the oil directly over the other ingredients.

Insert the immersion blender wand, pressing the head firmly against the bottom of the jar so that it fully covers the egg.

Turn the blender on high. Keep the blender head pressed to the bottom. Don’t lift it yet! You’ll quickly see a thick, white, creamy mixture begin to form at the very bottom of the jar.

Once you have a thick layer of mayo at the bottom, slowly lift the blender up and down to incorporate the remaining oil until all is thick and creamy. Taste for seasoning then add salt, lemon juice or extra vinegar to taste.