Preheat your oven to 400°F (200°C).
Toss the cubed butternut squash with olive oil, salt, pepper, and garlic powder in a bowl.
Spread the seasoned squash on a baking sheet and roast for 25-30 minutes, or until tender.
While the squash roasts, cook the macaroni according to package instructions until al dente.
Once the squash is done, let it cool briefly, then blend it with milk until smooth.
In a saucepan over medium heat, combine the blended squash mixture and cheeses, stirring until melted and creamy.
Mix the cooked macaroni with the cheese sauce, combining thoroughly.
Optional: Add cayenne pepper if desired, and mix well.
Transfer the mac and cheese to a baking dish and optionally top with extra cheese or breadcrumbs.
Bake in the oven for 15-20 minutes until the top is golden and bubbling.