Preheat your oven to 425°F and toss cubed butternut squash with 1 tablespoon olive oil, salt, and pepper on a baking sheet. Roast for 20-22 minutes until golden brown and fork-tender, stirring halfway through to ensure even caramelization. The squash should be soft enough to mash with light pressure.

While the squash roasts, bring a large pot of salted water to a rolling boil for your pasta. Add pasta and cook according to package directions until al dente, then drain but reserve 1/2 cup pasta water for later sauce adjustments.

Heat 1 tablespoon olive oil and 1 tablespoon butter in a large skillet over medium heat, then sauté diced onion until translucent, about 3-4 minutes. Add minced garlic and cook for 1 minute until fragrant, being careful not to burn the garlic.

Once the roasted butternut squash is ready, add it to the skillet with the garlic and onion mixture. Mash the squash partially with the back of a wooden spoon to create a chunky-textured base for your creamy silky roasted butternut pasta recipe sauce.

Pour in the vegetable broth and heavy cream, then add remaining 2 tablespoons butter, sage, nutmeg, and red pepper flakes. Stir constantly over medium heat for 2-3 minutes until the sauce becomes smooth and silky, adjusting thickness with reserved pasta water if needed.

Add the cooked pasta to the skillet and toss gently to coat every strand with the creamy roasted butternut sauce. Fold in grated parmesan cheese gradually while stirring, allowing the heat to melt it evenly throughout the dish.

Taste and adjust seasoning with additional salt, pepper, or nutmeg according to your preference. Cook for 1-2 minutes more to let flavors meld before serving this family pasta immediately while it's warmest.