Preheat your oven to 375°F (190°C).
Cook the elbow macaroni according to package instructions; drain and set aside.
In a pot, boil water and add diced butternut squash until tender, about 10 minutes.
Drain the squash and blend it until smooth.
In a saucepan, melt butter over medium heat.
Whisk in flour to create a roux, cooking for 1-2 minutes.
Gradually add milk while whisking until smooth and thickened.
Stir in the blended squash, garlic powder, salt, and pepper.
Add the cheddar and mozzarella cheese; stir until melted and creamy.
Combine the cheese sauce with the macaroni, mixing well before transferring to a baking dish.
Sprinkle breadcrumbs on top for added crunch if desired.
Bake for 20 minutes until bubbly and golden.