Bring well-salted water to a boil and cook the fresh fettuccine until al dente
In a large bowl (not on direct heat), add the cubed butter
Transfer the pasta directly into the bowl
Add a splash of hot pasta water and toss vigorously until the butter melts and begins forming a creamy emulsion
Add the Parmigiano gradually while tossing continuously
Add more pasta water as needed, a little at a time, until you get a smooth, glossy, creamy sauce that coats every strand
Serve immediately while silky and fluid
