Using a peeler, peel the outer/tough skin off of each white asparagus. Remove more than you think you should, and any stringy pieces.
Snap the bottom of the asparagus off, it will naturally break towards the bottom end, ( the bottom inch or two of the asparagus). When you snap the asparagus, if you see any strings, lift them off because this is part of the tough outer skin.
Put water, salt and 1 Tbs lemon into a pan and boil. Then put the peeled asparagus inside the water, reduce the heat to Medium and cook for about 12 minutes, or until you can easily stab the asparagus with knife and the asparagus is soft. Remove the asparagus from the water.
Then make Provençal Lemon Mustard Mayo. Put 1 egg yolk, 2 tsp mustard, and salt in a food processor and mix until thick. (You can also mix this with a handheld electric mixer). Add the oil slowly, lemon juice and herbs de provence, and mix.
Pour the mayo on top of the asparagus.