Now let's make the simple dressing! Place the avocado oil, egg, mustard powder, lemon juice and salt in a tall container (I use a 2 cup Pyrex measuring cup). Place an immersion blender at the bottom and turn on. Once the mixture starts to blend together and become thick, move the immersion blender towards the top, until it is well blended. This should take less than a minute! **If using a regular blender be sure to see the note below this recipe.