Make a healthier mac and cheese with this version from Joy Bauer.
Preheat oven to 400˚F.
If using block cheese, shred the cheese using the large side of a box grater, and set it aside.
Mist a baking sheet with oil spray and add the cubes of butternut squash. Mist the tops of the butternut squash with oil spray and sprinkle with ¼ teaspoon kosher salt. Place baking sheet in oven and roast for about 20 minutes or until squash is cooked through. Allow to cool before adding cubes to a blender or food processor and pureeing. Set aside. Reduce oven temperature to 350˚F.
While butternut squash bakes, prepare the pasta and cheese sauce: Bring a large pot of unsalted water to a boil. Add the macaroni and follow the directions on the package for al dente pasta, about 7 minutes. Drain and return to pot.
In a large saucepan, combine 1 cup of milk with onion powder, dry mustard, paprika, remaining ¼ teaspoon kosher salt, black pepper, and hot sauce. Place over medium heat, and cook until the mixture comes to a gentle simmer.
In a small bowl or cup, mix the cornstarch with remaining ¼ cup cold milk. Add the cornstarch mixture to the saucepan and stir to combine. Return sauce to a simmer and cook for 2 to 3 minutes, stirring occasionally. The mixture should thicken slightly.
Remove the saucepan from the heat and add the shredded cheese. Continue stirring until the cheese is completely melted and no lumps remain.
Pour the butternut squash puree into the cheese sauce and stir until combined, then add the butter and stir until it is completely melted and combined.
Add the sauce to the cooked macaroni and stir until everything is evenly coated. Transfer to a 9 x 13-inch baking dish coated with oil spray. Sprinkle with Parmesan and place under a preheated broiler for 4 to 7 minutes, or until the top is golden brown and crispy; check often to make sure cheese does not burn.
Variation: Make mac and cheese muffins by splitting the mixture among 20 standard muffin tins (about 1/3 cup in each). For this variation, add an additional tablespoon of cornstarch to the milk mixture, in order to help the muffins stay firm. Sprinkle each muffin with Parmesan over the top and bake for 30 minutes, or until tops are slightly browned. Remove from oven and allow to cool for 5 minutes so cheese (and muffin) can firm.