Step 1: Preheat the oven to 350ºF. On a large baking sheet, combine the butternut squash with 2 tablespoons of olive oil, ensuring it is evenly coated. Season generously with salt and black pepper. Roast in the oven until the squash is tender and golden, approximately 35 to 40 minutes.
Step 2: While the squash is roasting, bring a large pot of salted water to a boil. Cook the pasta until al dente, then drain, reserving ½ cup of the pasta water for later use.
Step 3: In a large skillet over medium heat, melt the butter and add the remaining 2 tablespoons of olive oil. Introduce the minced garlic, chopped sage, and walnuts, stirring frequently until fragrant, about 2 minutes. Gently fold in the roasted butternut squash and cook for an additional 30 seconds. Incorporate the drained pasta along with the reserved pasta water, seasoning with salt and pepper to taste. Toss everything until well combined.
Step 4: To finish, sprinkle the pasta with crumbled gorgonzola and cacao nibs, if desired, before serving. Enjoy the comforting flavors of this delightful autumn dish!