Spaghetti with scallops and onions
Description
In a large pot of boiling salted water, cook spaghetti until al dente. Reserve 1 cup of the cooking liquid, then drain the pasta and return it to the pot. Meanwhile, heat 1 tablespoon of butter in a large skillet over medium-low heat. Add leek and garlic, season with salt and pepper, and cook, stirring, until the leek is tender, about 6 to 8 minutes. Add the leek mixture to the pot with the pasta. In the same skillet, heat 1 tablespoon of butter over medium heat. Add scallops and lemon zest, and cook, stirring, until scallops are just done, about 2 to 3 minutes. Transfer scallops to the pot with the pasta. Add tarragon, the remaining 2 tablespoons of butter, and lemon juice, and toss to combine. Add enough of the reserved cooking liquid to moisten. Serve immediately.