In a large pot of boiling salted water, cook the pasta, stirring often, until al dente. Drain (**this is very important) reserving 2 cups pasta cooking water.

Set a large skillet over medium-low heat and add 1-cup pasta water. Bring just to a low simmer, then whisk in 1 tablespoon of butter, one piece at a time, until melted.

Gradually add the cheese, whisking constantly, being sure it is melted and incorporated thoroughly before adding each addition.

Whisk in the additional 1-cup pasta water.

Add the pasta and mix to coat until noodles are covered in sauce.

(Note – if using cubed chicken, add it now and mix well.)

Taste and season with kosher salt and freshly ground black pepper, if desired.

Cook over low heat, about 3-5 minutes, just until the pasta absorbs most of the liquid. Stir often to avoid scorching the cheese-covered pasta.

To serve, place 1/4th of the pasta on a plate and add 1 sliced chicken breast.

Top with a heaping helping of grated Parmesan cheese and garnish with chopped fresh parsley or basil leaves.

Enjoy!