Preparation Preheat oven to 250°F. Melt butter in a heatproof serving bowl in middle of oven, about 5 minutes. Cook fettuccine in a 6- to 8-quart pot of boiling salted water until al dente. Reserve 1/2 cup pasta cooking water, then drain fettuccine in a colander. Immediately toss fettuccine with butter and salt in bowl, then slowly add 3/4 cup cheese, tossing constantly and adding enough of cooking water to keep pasta moist. Season with salt and pepper to taste, then sprinkle with remaining cheese.