In a blender ready recipient put:

Light olive oil 200 ml to start

One (room temperature) egg

Pinch of Salt

10 drops of lemon (a little squeeze)

A little of a garlic clove, optional according to taste; for garlic mayonesse add more

Put the blender to the bottom and whiz (don’t move!)

Slowly start moving blender up and slowly add an extra 100 ml of olive oil

Keep Calm & Persist!

(Or you can do it by hand! Not recommended!)