There are three things to know about (white) asparagus in order to cook it well.

1. Buy them fresh and thick (between 15-30mm in diameter). Look at the bottom of the bunch to check it.
2. Peel them well. Take at least 1mm off, especially from thickest ones.
3. Cook for 20-25 minutes (boil or steam). After boiling they might be too watery, so let them cool down on a colander or fry them all over in butter.

For the sauce you can use mayonnaise, but it's not really healthy and original. We tried the following sauce:

1. Blend or cut into dust fresh parsley, garlic and chives (I guess fresh dills, basilic or origan would also be good).
2. Add cottage cheese (20% fat or even diet) and some sour cream.
3. Add some milk if the sauce is too thick.

Buon appetitto!