Leeks Vinaigrette

Ingredients

For 4 servings

• •2 quarts (1.9 L) tap water
• •1 1/4 ounces Diamond Crystal kosher salt (36 g; 1/4 cup plus 1/4 teaspoon), divided; for table salt, use half as much by volume
• •4 small leeks (6 ounces; 170 g each), white and light green parts (see notes)
• •1 1/2 tablespoons (22 ml) sherry vinegar or red wine vinegar
• •1 c. à soupe (9 g) finely chopped shallot, from 1 medium shallot
• •2 c. à café whole-grain mustard
• •1 c. à café Dijon mustard
• •1 /4 teaspoon freshly ground black pepper
• •3 c. à soupe (45 ml) extra-virgin olive oil
• •1 hard-boiled egg, chopped
• •1 c. à soupe chopped fresh flat-leaf parsley
• •1 c. à café capers

Method

1. 1.In a 4-quart saucepan, bring water and 1/4 cup salt to a boil over high heat. While water comes to a boil, trim roots from leeks, taking care to leave base intact. Halve leeks lengthwise, stopping 1-inch above the base. Rinse leeks thoroughly under cool running water to remove any dirt between layers. Using kitchen twine, tie both halves of each leek about two-thirds of the way up to hold them together. Line a plate with paper towels or a clean kitchen towel; set aside.
2. 2.Lower leeks into boiling water; reduce heat to medium-low, and cook, covered, until base of leek can be easily pierced with a paring knife, about 12 minutes. Using tongs or a spider skimmer, transfer leeks to a paper towel-lined plate, allowing excess water to drip off. Let rest at room temperature until cool enough to handle, about 10 minutes.
3. 3.While leeks cool, place sherry vinegar and shallots in a medium bowl and let sit for 5 minutes. Whisk in whole-grain mustard, Dijon mustard, pepper, and remaining 1/4 teaspoon salt. Slowly stream in olive oil, whisking vigorously and constantly, until emulsified and creamy. Set vinaigrette aside.
4. 4.Remove twine from leeks. Completely halve leeks lengthwise, and arrange, cut side down, on paper towel-lined plate. Place paper towels on top of leeks, and gently press down on leeks to remove any excess water.
5. 5.Spread half (40 ml) of the vinaigrette evenly over platter. Arrange leeks, cut side up, on platter; drizzle with remaining vinaigrette. Garnish with hard-boiled eggs, parsley, and capers.