Step 1

Bring a large pot of heavily salted water to a boil. Meanwhile, finely grate 1 1/2 ounces Parmesan cheese and 1 1/2 ounces Pecorino Romano cheese (about 1 cup each grated on a microplane or 1/2 cup each grated on the small holes of a box grater).

Step 2

Add 1 pound dried fettuccine to the boiling water. Cook according to package directions, stirring frequently as fettuccine is prone to clumping, until al dente, 8 to 10 minutes. Reserve 3/4 cup of the pasta water, then drain the pasta.

Step 3

Melt 4 tablespoons unsalted butter in a large skillet over medium heat. Stir in the Parmesan cheese, Pecorino Romano cheese, 2 cups heavy cream, 2 finely grated garlic cloves, 3/4 teaspoon kosher salt, 1/4 teaspoon freshly grated nutmeg, and 1/4 teaspoon black pepper. Simmer, stirring frequently, until the sauce thickens and the sauce turns glossy, 3 to 5 minutes.

Step 4

Add the pasta and 1/4 cup of the reserved pasta water and toss to coat. Add more of the reserved pasta water a tablespoon at a time if needed to get a saucy consistency. Taste and season with kosher salt as needed. Garnish with coarsely chopped parsley leaves and more Parmesan if desired. The sauce will thicken as it sits, so you may need to toss in more pasta water if you go back for seconds!