Preparation: Allow the egg to come to room temperature, then crack it into a bowl. Add the grapeseed oil to the immersion blender container. Add the Dijon Mustard. Add the White Vinegar.
Lemon: Squeeze the juice of one lemon or lime. The lemon should yield approximately two to three tablespoons of lemon juice. Add it to the container.
Emulsification: Add the immersion blender to the bottom of the container and blend for approximately six to eight seconds, working your way up to ensure all ingredients are emulsified. The entire process should take ten to fifteen seconds. At first, you will notice plumes of a creamy substance almost cloud-like; thereafter, the mayonnaise should form quickly. Once thoroughly emulsified, taste and check the flavour.
Taste test: Add more vinegar for a sharp, tart taste. And if you would like, add more lemon juice to reduce the taste of the oil. Generally, Grapeseed oil will have a very neutral taste; vinegar, Dijon mustard, and lemon play a considerable role in creating that traditional mayonnaise taste.