The first tender asparagus that pops up in stores and farmers markets is perfect for this recipe, because it is completely different from the stuff that passes for asparagus the rest of the year. Choose spears that do not have woody ends or mushy tops.
Because the egg remains raw, use a pasteurized egg if you have food-safety concerns.
Make Ahead: The mayonnaise can be covered and refrigerated for several hours or up to 1 day in advance, although it is best served the same day it is made.
- 1 large egg yolk (see headnote)
- 1 teaspoon Dijon-style mustard
- Juice from 1/2 lemon (2 teaspoons; may substitute white wine vinegar)
- 1 cup vegetable, sunflower, peanut or olive oil, or a combination thereof
- Leaves from 3 stems of chervil, finely chopped (2 teaspoons; may substitute finely chopped fresh fennel leaves)
- 1/8 teaspoon fine sea salt (optional)
- 1 pound asparagus (see headnote)
- 2 small or medium fennel bulbs (outer layer discarded), trimmed
Use a balloon whisk or hand-held electric mixer to whisk together the egg yolk, mustard and lemon juice in a medium bowl. Add 1 drop of oil, whisking until completely incorporated. Repeat with a second drop of oil, and then another, until you can eventually pour a thin stream of oil while whisking constantly to form a mayonnaise. This is a process that will take 3 to 5 minutes and shouldn’t be rushed.
Add the chervil and the salt, if desired; mix well, then pour the mayonnaise into a small serving bowl.
Just before serving, trim off the bottom ends of the asparagus. If the skin seems thick near the bottom, use a vegetable peeler to remove it. Cut the fennel from top to bottom into thin slices; their lengths will vary.
Serve the vegetables on a platter or individual plates, with the mayonnaise on the side.
From Gastronomer Andreas Viestad.
Tested by Bonnie S. Benwick.
E-mail questions to the Food Section at email@example.com.