1Remove egg from refrigerator about 30 minutes prior to making mayonnaise.
2Into a wide mouth mason jar, or other cylindrical vessel, crack egg and add remaining ingredients.
3Place immersion blender all the way into the bottom of jar. Turn on, and blend for about 20 seconds. Without stopping the blender, slowly begin to lift blender up from the bottom of jar, circling slowly as you do to ensure all of oil gets blended.
4That's it! You should have creamy, spreadable mayo that is full of good stuff, and free from questionable ingredients. Place lid onto Mason jar, or transfer to another container. Store refrigerated for up to a week.