Farfalle with Kale Sauce / Farfalle con Salsa di Cavolo Nero

Directions

1. In a medium sauté pan, heat the olive oil over medium heat; stir in the leeks and cook just until they begin to wilt; stir in the garlic and continue cooking just until it softens. Cover and keep warm.
2. Fill a 4-quart pot with water and bring to a boil. Stir in the salt. Add the kale and cook until the kale wilts. Use a slotted spoon or spider to drain and transfer the kale to the sauté pan. Mix it well with the leek mixture.
3. Transfer the mixture to a blender or food processor.
4. Cook the pasta in the same pot the kale was in until al dente. It should be cooked through but not mushy; if the pasta does not hold its shape, it is overcooked.
5. Remove 1/4 cup of the cooking water and set aside. Drain the pasta and transfer it back to the pot.
6. Process the kale mixture adding 2 tablespoons of the reserved water. The sauce should have a smooth but not too thin consistency. If the sauce is too thick, add a little more water. It should have the consistency of heavy cream.
7. Add the sauce to the pot with the pasta; stir well to combine over low heat until it is hot. Add the lemon zest and cheese and mix well. Salt to taste.
8. Serve hot.