Step 1: Caramelize the Leeks Start by preparing your leeks. Remove the tops and cut them in half lengthwise, then thinly slice them. Heat 1 tablespoon of olive oil and 1 tablespoon of butter in a large skillet over medium heat. Add the sliced leeks, along with ½ teaspoon of salt and ½ teaspoon of granulated sugar. The sugar helps with the caramelization process, drawing out the natural sweetness of the leeks. Cook the leeks for about 20 minutes, stirring occasionally. If they start to dry out before caramelizing, add a splash of water to the pan. You’re looking for them to turn a deep golden brown and develop a sweet, concentrated flavor. This slow cooking process is essential for developing the depth of flavor that makes this dish special. Once the leeks are beautifully caramelized, add ⅓ cup of sherry wine (you can also use white wine or chicken broth as alternatives). Let it cook until the liquid is reduced and almost evaporated, scraping up any browned bits from the bottom of the pan. This deglazing step adds another layer of flavor to the dish.

Step 2: Brown the Mushrooms Remove the caramelized leeks from the pan and set them aside. Add the remaining 2 tablespoons of butter to the same skillet and heat over medium-high heat. While the butter is melting, prepare your mushrooms by cleaning them and slicing them if they’re large. Add the mushrooms to the hot butter, taking care not to overcrowd the pan. This is a crucial tip because overcrowding prevents proper browning and can make the mushrooms steam instead of sear. If necessary, cook the mushrooms in batches. Let them cook undisturbed for a few minutes to develop a nice brown color, then flip and cook until browned on all sides. Season the mushrooms with a pinch of salt, then add 4 minced garlic cloves and 2 sage leaves to the pan. Cook for another minute or two until the garlic becomes fragrant but not browned. The aroma of garlic and sage will fill your kitchen, signaling that you’re well on your way to creating something delicious.

Step 3: Create the Creamy Sauce Return the caramelized leeks to the pan with the mushrooms. Pour in ¾ cup of heavy cream, 1 tablespoon of balsamic vinegar, and 1 teaspoon of lemon zest. Stir everything together and let the mixture simmer gently. The sauce will begin to thicken as it cooks. While the sauce simmers, cook your pasta according to the package instructions until al dente. Before draining, reserve 1 cup of the pasta water. This starchy water is a secret weapon for adjusting sauce consistency and helping it cling to the pasta. Pro tip: The reserved pasta water is essential for achieving the perfect sauce consistency. If your sauce seems too thin, gradually add the pasta water a little at a time until you reach the desired thickness.

Step 4: Combine and Finish Add the cooked pasta directly to the pan with the sauce. Pour in about half of the reserved pasta water, then add ½ cup of grated gruyere cheese and 1 teaspoon of black pepper. Toss everything together gently, allowing the cheese to melt and the sauce to coat every strand of pasta. If the sauce seems too thick, add more of the reserved pasta water a little at a time until you reach the desired consistency. Continue tossing and simmering for another minute or two until everything is well combined and the pasta is coated in a creamy, glossy sauce. For a finishing touch, sprinkle ¼ cup of toasted pine nuts on top before serving. This optional garnish adds a delightful crunch and nutty flavor that complements the dish beautifully.