Add room temperature egg yolk to food processor and mix for 20 seconds, then add salt, vinegar and dijon for another 20 seconds together.
Scrape sides and this part needs to be consistent and VERY slow. Turn processor on again and very slowly add the oil in and watch as it thickens, continuing to slowly slowly adding it to incorporate together and become the texture of mayo. Enjoy.
**** If you are making Mexican you will add the seasonings and lime juice once oil is incorporated completely adding slowly with the juice during an additional 10 seconds.
Scrape down sides and taste. If you want a bit more heat, salt or lime juice to thin out do so at this time folding together with a spatula until it is just right for you.