Preheat the oven to 400°F. Cut the top off the garlic head to expose the cloves. Place the garlic on a piece of aluminum foil, drizzle generously with olive oil, and sprinkle with a little salt. Wrap tightly in foil.
Add the cubed butternut squash to a baking sheet or baking dish. Drizzle with olive oil and season with paprika, all-purpose seasoning, and salt. Toss until evenly coated.
Place the butternut squash and foil-wrapped garlic in the oven. Roast the squash for approximately 25–35 minutes, or until fork-tender and lightly caramelized. The garlic may need an additional 10–15 minutes until the cloves are soft and golden.
While the vegetables are roasting, cook the rigatoni according to the package instructions until al dente. Before draining, reserve 1 cup of pasta water.
Once the garlic is soft, squeeze the roasted cloves out of their skins. Add the roasted butternut squash, roasted garlic, and ½ cup of reserved pasta water to a blender. Blend until completely smooth and creamy. Add more pasta water as needed.
Pour the butternut squash sauce into a large skillet or saucepan over medium-low heat. Stir in the heavy cream and freshly grated Parmesan cheese until combined.
Add red pepper flakes and adjust the salt and seasonings to taste. If the sauce is too thick, gradually add more reserved pasta water until it reaches your desired consistency.
Add the cooked rigatoni to the sauce and toss until every piece is evenly coated.
Finish with extra Parmesan cheese or red pepper flakes if desired. Serve warm and enjoy!