Poached Arctic Char with Basil-Tarragon Mayonnaise

Directions

1. 1.

   Blend egg yolks, lemon juice, and mustard powder in a blender. Add basil and 1/4 cup tarragon. With machine running, drizzle in 3/4 cup oil; blend until smooth. Transfer mayonnaise to a small bowl, cover, and chill.

2. 2.

   Combine tarragon sprigs, garlic, 2 tablespoons kosher salt, and 6 cups water in a large deep, lidded skillet and bring to a boil. Add fish, cover, and remove skillet from heat. Let stand until fish is just opaque in the center, 6-8 minutes.

3. 3.

   Meanwhile, cook asparagus in a large pot of boiling salted water until crisp-tender, about 3 minutes; drain

4. 4.

   Serve fish with asparagus; top with mayonnaise, drizzle with some oil, and sprinkle with sea salt.

5. 5.

   DO AHEAD: Mayonnaise can be made 2 days ahead. Keep chilled.