Bring a large pot of salted water to a boil and cook the fettuccine until just al dente. Reserve 1 cup of pasta water, then drain.
In the same pot, melt the butter over low heat. Add the hot pasta back to the pot.
Gradually sprinkle in the cheese while tossing the pasta continuously to create a creamy sauce.
Add a splash of reserved pasta water if needed to loosen the sauce.
Season with salt and black pepper to taste. Serve immediately.