Step 1

Bring a large pot of lightly salted water to a boil.

Step 2

Meanwhile, toast peppercorns in a medium Dutch oven over medium heat, swirling often, until heated through and fragrant, about 3 minutes. Transfer to spice mill or mortar and pestle and let cool; reserve skillet.

Step 3

Cut guanciale into 1x½x¼" pieces. Arrange in reserved skillet and drizzle with a little oil. Set over medium heat and cook, stirring occasionally, until lightly golden brown and starting to crisp, about 5 minutes (don’t let pieces get too crunchy). Using a slotted spoon, transfer to a small plate.

Step 4

Add about ½ cup hot water from pot to skillet, scraping up brown bits with a wooden spoon. Set skillet aside.

Step 5

Whisk egg yolks, egg, and about three-quarters each of Parmesan and Pecorino in a medium bowl. Coarsely crush peppercorns and add all but a pinch to egg mixture; set remaining pepper aside for serving.

Step 6

As soon as pot of water is at a boil, cook pasta, stirring occasionally, until very, very al dente, about 4 minutes less than package directions.

Step 7

Using a spider or slotted spoon, transfer pasta to skillet with reserved guanciale liquid and set over medium heat (alternatively, scoop out about 2 cups pasta cooking liquid and drain pasta in a colander). Cook pasta, stirring occasionally, until liquid is simmering (you’ll be able to tell because the pasta will be steaming), about 1 minute.

Step 8

Whisking constantly, add about 1 cup pasta cooking liquid to egg mixture to warm it up. Add egg mixture to pasta and cook, tossing constantly, keeping the mixture below a simmer, and adding more pasta cooking liquid by the ½-cupful if needed to adjust the consistency, until sauce thickens just enough to lightly coat pasta, about 5 minutes. Do not rush this step or you risk ending up with a pan of pasta and scrambled eggs. Remove skillet from heat if you want to slow the process down. As soon as you see wisps of steam rising from the egg mixture, that’s a good indication that the sauce is about to go from very liquidy to perfectly thickened. Remove from heat and toss in guanciale.

Step 9

Divide pasta among plates. Top with reserved Parmesan, Pecorino, and pepper.