Taken from Cook’s Illustrated, January 2010
Serves 4 to 6.
4 oz finely grated Pecorino Romano cheese (about 2 C)
2 oz coarsely grated Pecorino Romano cheese (about 1 C)
1 lb spaghetti
2 Tbsp heavy cream
2 tsp extra-virgin olive oil
1 1/2 tsp finely grated black pepper
Bring 2 quarts water to boil in large Dutch oven. Add pasta and 1 1/2 tsp salt; cook, stirring frequently, until al dente. Reserve 1 1/2 C cooking water. Drain pasta.
Slowly whisk 1 C reserved pasta cooking water into finely grated Pecorino until smooth. Whisk in cream, oil, and black pepper.
Gradually pour cheese mixture over pasta, tossing to coat. Let pasta rest 1 to 2 minutes, tossing frequently, adjusting consistency with remaining 1/2 C reserved pasta water.
Serve, passing coarsely grated Pecorino separately.
The quality of ingredients seems to make a difference with this dish (I have made it a few times). The best cheese, olive oil, and pasta are a must! And, about the cheese. . . it really is important that the portion that gets melted in the pasta water is finely grated. The sauce will not be smooth without finely grated cheese. You could substitute half-and-half for the cream if the dish is too rich for you; it wasn’t too rich for me. Finally, be careful with the salt. The cheese is really salty and the pasta water is really salty. I didn’t need any salt besides that.
I tried another recipe for Cacio e Pepe. The recipe above had a lot more flavor and much better texture. I think it was because of the cooking water. Do not adjust the amount of water in the recipe; the thickness of the cooking water is essential to the taste of the sauce. Also, don’t forget to leave a few minutes for the pasta to rest. This was really important to the sauce, too.