1 measure (according to desired amount) unsweetened soy milk
2 measures oil (1 ½ parts sunflower oil, ½ part olive oil)
1 ½ teaspoon mustard
the juice from 1 lemon
salt, to taste
Place the soy milk in the blender, turn the blender on and slowly add the oil until it has the consistency of mayonnaise, if not add more oil.
Finally add the mustard, lemon juice and the salt.