Using an immersion blender:
In a wide-mouth Mason jar (or any glass container), add all ingredients (raw egg, oil, lemon juice, Dijon mustard, and a pinch of salt).
Place the immersion blender inside the jar. Turn it on, and using a slow up and down motion, blend all of the ingredients.
Blend for a minute or two, and DONE!
Use it in your favorite recipes right away and/or refrigerate it for up to a week in a lidded jar.
Using a food processor:
If using a food processor, DON NOT mix all ingredients at the same time!
First, add the egg, and blend for a few seconds until creamy (about 20 secs.).
Then, add the Dijon mustard, lemon juice, and salt and blend for another few seconds.
Important: Lastly, add the oil SLOWLY, in very tiny increments, to give it time to emulsify. If you add it all at once, your mayo will be runny instead of creamy.
