In a large pot, cook noodles in boiling salted water, until al dente, according to package instructions. Reserve ¼ of water, then drain and set aside.
In the medium pot, melt the butter over medium heat until it is no longer foaming. Whisk in flour, salt and pepper, and cook until it loses its flour smell, approximately 2 minutes.
Slowly add milk and heavy cream, whisking to combine. Bring to a slow boil. Reduce heat to low, and add in cheese, stirring until melted.
Add pasta to the cheese mixture and toss to combine. Add reserved pasta water by the teaspoon full until the desired consistency is achieved. Let sit 5 minutes to thicken, if desired.