Cook the Pasta: Begin by boiling water in a large pot and add a generous amount of salt once it reaches a rolling boil. Add the pasta of your choice and cook according to package instructions until al dente. Reserve about half a cup of pasta water before draining.
Sauté the Vegetables: In a large skillet, heat olive oil over medium heat and add the sliced leeks, stirring frequently until they begin to caramelize—about 5-7 minutes. Once softened, add in the cremini mushrooms along with minced garlic, continuing to sauté until everything is cooked through.
Create the Sauce: Pour in the dry white cooking broth (or vegetable stock) into your skillet with vegetables and let it simmer for about 3 minutes to reduce slightly. Next, add heavy cream to enrich the sauce while stirring consistently until combined.
Combine Pasta and Sauce: Add the drained pasta directly into your skillet with the sauce mixture, tossing gently to coat all strands evenly. If necessary, use reserved pasta water incrementally to achieve your desired consistency.
Add Cheese and Seasoning: Sprinkle shredded Gruyere cheese over your pasta mix while stirring until melted completely into a creamy blend alongside salt and freshly ground black pepper to taste.
Serve and Garnish: Plate your beautiful Caramelized Leek and Mushroom Gruyere Pasta, garnishing with chopped fresh parsley if preferred. Enjoy this delightful dish warm!