- 1 butternut squash, halved lengthwise and seeded
- 1 (16 ounce) package rotini pasta
- 2 tablespoons butter
- 2 tablespoons all-purpose flour
- 1/2 teaspoon dry mustard
- 2 cups milk
- 6 ounces shredded white Cheddar cheese
- 6 ounces shredded Cheddar cheese
- 1/4 cup seasoned dry bread crumbs, or as needed
- Preheat oven to 400 degrees F (200 degrees C).
- Place butternut squash, cut-side down, on a baking sheet.
- Roast squash in the preheated oven until soft, 40 to 50 minutes. Remove squash flesh from skin and set aside. Reduce oven temperature to 375 degrees F (190 degrees C).
- Bring a large pot of lightly salted water to a boil; cook the rotini at a boil until tender yet firm to the bite, about 8 minutes; drain.
- Melt butter in a large saucepan over medium heat. Whisk flour and mustard into melted butter until smooth, about 1 minute. Gradually whisk milk into flour mixture until the mixture has the texture of heavy cream, 5 to 7 minutes. Remove from heat.
- Stir butternut squash, white Cheddar cheese, and Cheddar cheese into milk mixture until cheese is melted. Stir rotini into cheese mixture. Pour cheese mixture into a 9×13-inch baking dish. Top with bread crumbs.
- Bake in the preheated oven until bread crumbs are golden, about 10 minutes.