Serves 4–6 | 35 minutes
- kosher or sea salt
- 1 pound whole-wheat spaghetti
- 2 large leeks, white and light green parts only, halved lengthwise (about 2 heaping cups)
- 2 tablespoons unsalted butter
- 1 tablespoon extra-virgin olive oil, plus more for serving
- black pepper, freshly cracked
- 2 cloves garlic, finely chopped
- pinch of red pepper flakes
- zest from 1/2 medium lemon
- 3/4 cup grated parmigiano-reggiano and/or pecorino cheese, plus more for serving
- 1/2 cup chopped parsley
- 1/2 cup crème fraîche
Fill a large pot with water and bring to a boil. Add a couple good pinches of salt and toss in the spaghetti. Cook according to package instructions, but pull from the heat 2 minutes shy of cooking time and reserve a cup of pasta water before draining. Drain and set aside.
Meanwhile, rinse the leek stalks under running water to remove any remaining dirt or sand, holding the layers together and peeling back a section at a time to clean. Pat dry with a clean towel. Place the leeks, cut-side face down, on a cutting board and slice them into half moons about 1/4” thick across the stalk.
Heat a large skillet over medium heat and add butter and olive oil. After the butter is melted and begins to foam, toss in the leeks. Sprinkle with salt and pepper and stir. Sauté until the leeks have softened a bit, but avoid letting them brown or caramelize; turn down the heat if need be.
Add garlic, red pepper flakes, and lemon zest. Stir and cook through for a minute or two. Spoon the cooked pasta into the skillet and stir in the cheese. Splash the reserved pasta water in, a little at a time, tossing as you go, until the noodles are creamy and evenly coated with a cheesy sauce. Stir in parsley. Taste and adjust seasoning.
Spoon pasta into bowls and top each with more cheese, a dollop of crème fraîche, and a drizzle of olive oil.