Cook fettuccine in a pasta pot of boiling salted water (2 TBSP salt to 6 quarts water) until al dente. Reserve 1/2cup cooking water, then drain pasta

Meanwhile, bring crea and butter to a simmer in a 12-inch heavy skillet over medium-low heat, adding 1/4 tsp salt and /2 tsp pepper

Add fettuccine, 1/4 cup reserved water, and cheese to sauce and toss. Add more cooking water if necessary.