All you need is Tonnarelli, Parmigiano reggiano, Pecorino romano and Black pepper
Salt the water. Not too much because the cheese is already salty.
Cook tonnarelli until very “al dente”
Drain pasta but keep some hot water.
Stir the pasta with the grated cheeses (adjust the mix on your taste because pecorino is very salty) and hot water.
Continue stirring adding cheese and hot water. In a couple of minutes you will have a nice cream. Serve immediately.
Add pepper. A lot of pepper :)