Add all ingredients to a tall container that can fit your immersion blender. Make sure there are no lemon seeds.
Blend with an immersion blender for 30 seconds, or until the ingredients get to a mayonnaise consistency.TIP: move the blender up and down in the jar to facilitate the process.
Taste and adjust for salt, lemon or garlic to your liking. When you are happy with the flavour, store in a jar in the refrigerator for up to 5 days.NOTE: if you want to have thicker mayonnaise, then add 3 more tablespoons of sunflower oil. If you want a thinner mayonnaise, then add 3 more tablespoons of soy milk.