01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - Toss cubed butternut squash with a drizzle of olive oil, salt, and pepper. Spread evenly on the baking sheet and roast for 20 to 25 minutes until tender and caramelized.
03 - Cook elbow macaroni according to package instructions until al dente. Drain and set aside.
04 - Melt unsalted butter in a large saucepan over medium heat. Add chopped onion and cook for 4 to 5 minutes until softened. Stir in minced garlic and cook for 1 additional minute.
05 - Add the roasted butternut squash, whole milk, salt, black pepper, nutmeg, and paprika to the saucepan. Simmer gently for 5 minutes.
06 - Use an immersion blender or transfer the mixture to a blender to purée until smooth and creamy. Return to the saucepan if necessary.
07 - Stir in grated sharp cheddar and Parmesan cheese until melted and sauce is smooth. Adjust seasoning to taste.
08 - Add the cooked pasta to the sauce and toss thoroughly to coat evenly.
09 - If desired, preheat the broiler. Mix panko breadcrumbs with melted butter. Sprinkle evenly over the pasta in an ovenproof dish and broil for 2 to 3 minutes until golden and crisp.
10 - Serve the dish hot immediately after preparation.