- 3/4 pound linguine
- 4 tablespoons (1/2 stick) unsalted butter, cut into pieces
- 2 leeks, white and light green parts only, halved and sliced
- kosher salt and black pepper
- 2 cups shredded rotisserie chicken (from 1/2 of a chicken), warm
- 3 tablespoons Dijon mustard
- 1 romaine heart, thinly sliced
- 2 tablespoons chopped tarragon
- Cook the pasta according to the package directions. Reserve 1 cup of the cooking water; drain.
- Meanwhile, heat 2 tablespoons of the butter in a medium skillet over medium-high heat. Add the leeks and ¼ teaspoon each salt and pepper. Cook, stirring occasionally, until tender, 2 to 4 minutes.
- Add the pasta, chicken, Dijon, the remaining 2 tablespoons of butter, and ¾ cup of the cooking water to the leeks and toss to coat (adding more cooking water as needed to loosen the sauce). Add the romaine and toss to combine.
- Serve warm, topped with the tarragon.