Cook the pasta to the box's specifications in a large pot. Drain and return to the pot. Add in cooked butternut squash; stir. Set aside (the heat from the pasta will start to soften the butternut squash).
In a medium saucepan, melt butter over medium-low heat. Add in flour, and whisk until it forms a roux. Continue to whisk constantly for about 1 minute (this will cook out the taste of the flour).
Add in milk, slowly, whisking constantly. Once the milk and the roux have been mixed together, turn the heat to low, and whisk the mixture for 4-5 minutes, until it has thickened. Remove from the heat and add in cheese, stirring until melted. Add in salt and pepper. Stir.
Add the cheese sauce to the pasta and butternut squash, and heat on low for 10 minutes (or until well heated through), stirring occasionally. The butternut squash will begin to cook down, adding to the creaminess of the sauce.
Serve immediately, and top with parsley, if desired. Pair with Clos du Boise Chardonnay.
Enjoy!