In a mixing bowl, add Egg (2), Dijon Mustard (1 tablespoon), juice of the Lemon (1/2), and Salt (1 pinch) and whisk. If using a food processor or blender, add directly into the cavity.
While combining with your whisk or blender, slowly add Grapeseed Oil (350 milliliter) in a steady stream.
Continue until the mixture thickens and turns a uniform, pale yellow. If it seems too thick, add more lemon juice or water. If it’s too thin, continue to add oil a small amount at a time and mix. Taste and adjust salt if needed.