16 ounces (450 grams) fettuccine
1/2 pound (227 grams) unsalted butter
2 cups (150 grams) freshly grated Parmigiano-Reggiano, plus more for garnish
salt and pepper
freshly grated nutmeg for garnish
Bring 4 quarts of water to a boil. Add 1 tablespoon (15 grams) salt, then add the fettuccine and cook according to package directions (or until al dente). Reserve 1 cup (235 mL) cooking water, then drain.
Meanwhile, melt half the butter and transfer to a large serving dish. Sprinkle with 1/2 cup (40 grams) cheese. Slice the remaining butter into thin pats and set aside.
Transfer cooked pasta to buttered platter. Top with pats of butter and remaining cheese. Toss with tongs or large fork and spoon to thoroughly combine pasta with cheese and butter. Add pasta water as needed to make a sauce. Season with salt and pepper to taste.
Garnish with additional cheese and freshly grated nutmeg, if desired.