Leeks in Vinaigrette (French Poireaux à la Vinaigrette)

Despite being a timeless classic, it's probably been a while since you made this dish. Entertaining bonus: It gets better as it sits, which means you'll be rewarded for making it ahead of time.

4 large leeks, white and pale-green parts only, tough outer layer removed
kosher salt
1 small shallot, finely chopped
½ clove garlic, finely grated
1 Tbsp. Sherry vinegar or red wine vinegar
1 tsp. Dijon mustard
1 tsp. whole grain mustard
½ tsp. fresh thyme, finely chopped
¼ tsp. sugar
¼ cup extra-virgin olive oil
black pepper, freshly ground

Trim root end of leeks (leave as intact as possible so they don't break apart while cooking) and cook in a large pot of boiling salted water until meltingly tender (a paring knife should go all the way through with no resistance), 15-20 minutes. Transfer to paper towels to drain; let cool.

Whisk shallot, garlic, vinegar, Dijon and whole grain mustards, thyme, and sugar in a small bowl. Gradually whisk in oil and 1 Tbsp. water; season vinaigrette with salt and pepper.

Halve leeks lengthwise and arrange on a platter, cut side up; drizzle with vinaigrette and let sit at least 10 minutes before serving.

Make-Ahead: Leeks can be made 1 day ahead. Cover and chill. Bring to room temperature before serving.

Makes 4 servings.