Add aquafaba to a tall glass jar along with Dijon mustard and apple cider vinegar. Blend on high speed with a hand blender (or mix on stand blender ) for 30 seconds or until frothy.
With the immersion blender on its highest speed, slowly pour in the oil over the course of 1-2 minutes.
Taste and add salt as needed and wholegrain mustard if using, then stir.
Serve immediately or transfer to a sealed container and store in the refrigerator until cold - about 3 hours. It will thicken even more in the fridge!
NB: Both an immersion blender and small stand blender will work, but an immersion blender does produce a more thick and creamy mayo. (With the vertical blender follow the same method but it will take longer then 2 minutes to make the mayo and you must pour the oil much more slowly. This method could overheat the mixture and lead to a less creamy vegan mayo).
How to store the easy vegan mayonnaise with aquafaba
Store leftovers in the refrigerator up to 1 week. To store it longer, you must pasteurize the vegan mayo to eliminate pathogens and extend shelf life ( as you do for jams and preserves ).