Indeed, many vegetables are green. But that only happens because of the sun light, which stimulates the development of chlorophyll in the plant. Thus most plants growing above ground will be green, but plants growing underground (or even the parts of the plants growing underground) will generally not be green.
This explains why Northern European asparagus can be white: they are grown completely underground in specially formed earth structures. Harvesting these asparagus is a delicate manual job. This contributes to the price of fresh asparagus, but trust me, it is worth it!
In the Netherlands, as in surrounding countries, quality white asparagus are often divided into three categories: A, AA and AAA. These categories refer to the diameter of the asparagus.
- A: 16 - 20 mm diameter
- AA: 20 - 28 mm diameter
- AAA: 28 - 38 mm diameter.
The outside of the asparagus is rather tough, woody and stringy. You will have to peel the asparagus thoroughly in order to avoid unpleasant surprises during dinner. You will have to be very careful to avoid breaking the precious asparagus.
I use a simple vegetable peeler. Take an asparagus, put it on top of a cutting board, and peel from just below the top toward the bottom, meanwhile keeping the asparagus tight against the board. Go around until you have removed all of the the woody skin.
Now remove the tougher bottom of the asparagus. With the first asparagus, cut of the bottom 1 cm. If you feel a lot of resistance cutting through, repeat and cut of another centimeter. Repeat until you are satisfied that the tough end has been removed.
Boiling or Steaming
I personally prefer to steam white asparagus. That is mainly because my kitchen features an asparagus steaming pan (which, by the way, is great for steaming corn on the cob as well).
Of course, the steaming time depends on the diameter of the asparagus stalks. I use a sharp kitchen knife to test the doneness of the asparagus. I start testing after about eight minutes, and then every two minutes after that, until the knife goes in smoothly.
Once you are satisfied, take the steaming pot off the heat and keep the lid off to prevent the asparagus from overcooking.
In Germany and surrounding countries, white asparagus is often served as a main course. During asparagus season, some restaurants offer three to five course meals, featuring asparagus in each of the courses!
My favorite way to serve white asparagus is with Hollandaise Sauce, a boiled potato (great th finish the last of the Hollandaise with) and a boiled egg, sprinkled with some fresh flat-leave parsley.