Preheat oven to 375°F.
Steam Mann™ Butternut Squash “Rotini” in the microwave according to package directions, approximately 3 minutes. Remove from the microwave and set aside.
In a pot of salted boiling water, cook pasta until slightly under-cooked, about 7 minutes. Drain well and set aside.
Meanwhile, heat the milk in a small saucepan, being careful not to bring it to a boil. While the milk is heating, melt 6 tablespoons of butter in a large pot and add the flour. Reduce heat to medium and whisk for 2 minutes.
Continue whisking and add the hot milk. Stir about 2 minutes more until thickened and smooth. Remove the pot from heat and add the cheese, mustard, salt and pepper, mixing well until the cheese is melted and incorporated into the sauce. Add the cooked butternut squash and pasta and stir well. Pour into a 3-quart baking dish.
Melt the remaining 2 tablespoons of butter, combine butter with the breadcrumbs, and sprinkle on top. Bake 30-35 minutes, or until the sauce is bubbly and breadcrumbs are browned.
Serve as a side dish.