Boil the pasta according to package instructions. Drain.
Meanwhile, melt the butter in a medium saucepan over a medium-low heat. Whisk in the flour and cook for 1 minute, whisking.
Whisk in the milk, a little at a time, stirring until thick and creamy.
Stir in the pumpkin, cheese, mustard, sage, nutmeg, salt and pepper, stirring until the cheese melts.
Pour in the drained pasta and stir to coat.
Serve and enjoy!
Notes
When choosing pasta for mac and cheese, the best kinds are the ones with swirls and twirls such as rotini, shells, or elbow macaroni. This helps the sauce stick to the pasta to get the right amount of sauce in every bite.
When whisking the milk into the sauce, make sure you do it slowly as the flour needs time to absorb the milk and thicken.
Make sure you purchase pumpkin puree and not pumpkin pie filling as the filling contains spices and sugar that is used to make sweet pie desserts.