Bring a large pot of salted water to a boil. Add the butternut squash pieces and cook for about 10–15 minutes, or until they are fork-tender. Once soft, drain the squash and transfer it to a blender. Puree until you achieve a smooth consistency.

While the squash is cooking, bring another pot of salted water to a boil. Add your choice of pasta and cook according to the package instructions, typically around 8–12 minutes, until al dente. Reserve 1 cup of the starchy pasta water before draining.

In a non-stick skillet, heat over medium heat. Add the spicy chicken Italian sausage, breaking it apart with a wooden spoon. Sauté for about 7-10 minutes until browned. Remove from the skillet and set aside.

Lower the heat to medium-low, add the whipped butter, then toss in chopped shallots and minced garlic, sautéing for about 3–5 minutes until soft and golden.

Stir in the pureed butternut squash, season with kosher salt and pepper to taste, and gradually add the reserved pasta water until you reach your desired sauce consistency.

Add the baby spinach, fresh shaved Parmesan cheese, and sage leaves into the skillet, stirring until the spinach wilts and the cheese melts. Return the cooked sausage and add the drained pasta, mixing everything together.

Transfer the pasta to serving plates, garnishing with additional Parmesan cheese and a pinch of cracked black pepper. Serve warm.