Preheat oven to 350 degrees F. Cut your squash lengthwise in half and using a spoon scoop out the seeds. Place the pieces skin side down on a baking sheet and roast for 1 hour. When cool to the touch, scoop out 1 cup and add to a blender.
If frozen, defrost before baking, otherwise bake for 30-40 minutesm (turning the pieces over halfway through) or until soft all the way through.
Boil salted water in a large pasta pot. Add in pasta and cook al dente according to box instructions.
While pasta is cooking, add all other ingredients to the blender with the butternut squash and blend on high for about 30 seconds or until creamy. When pasta is done, drain and toss the pasta in your "cheese" sauce. You can add more salt and/or pepper to taste and then enjoy immediately!
Place breadcrumbs in a saute pan on medium-high heat and stir continuously until they begin to brown and become fragrant, about 1-2 minutes.
Remove from heat and top your mac and cheese with your toasted breadcrumbs!
Do not put the dish in the oven to heat up--it will dry out!
I recommend making the pasta fresh so its hot before serving, however, if you want to serve this dish later for a party or as leftovers, I recommend keeping the sauce and pasta separate and heating the sauce in a pan on the stovetop or in the microwave (if you must!) before mixing it together. You can just drizzle some olive oil on the pasta to keep it from sticking together.