Step 1

Bring a large pot of water to a boil over medium-high heat. Meanwhile, finely grate 1 ounce Pecorino Romano cheese on a Microplane (2/3 to 1 scant cup). Cut 1 (8-ounce) piece guanciale into 1/2-inch wide by 3/4 to 1-inch long pieces (about 1 1/2 cups).

Step 2

Place the guanciale in a large skillet, preferably nonstick. Cook over medium heat until it starts sizzling, about 2 minutes. Reduce the heat to medium low and cook, stirring occasionally, until the guanciale is browned and crisp, 6 to 10 minutes more.

Step 3

Meanwhile, add 1 pound dry spaghetti and 2 teaspoons kosher salt to the boiling water. Cook according to package directions until the pasta is just al dente, 8 to 12 minutes. Place 4 large eggs and 2 large egg yolks in a medium bowl and whisk until combined. Add the Pecorino and a pinch of kosher salt, and whisk until combined.

Step 4

When the guanciale is ready, transfer to a plate with a slotted spoon. Add 1 teaspoon coarsely ground black pepper to the skillet, turn off the heat, and stir to combine. Let cool for 1 minute.

Step 5

While whisking constantly, slowly stream in 1 tablespoon of the fat from the skillet into the egg mixture, then slowly stream in 1/4 cup of the pasta cooking water.

Step 6

When the spaghetti is ready, turn off the heat, then transfer it directly to the skillet with tongs. It’s ok if some water clings to the pasta. Add 1/4 cup pasta water to the skillet and toss until the pasta is well coated and most of the water and fat in the pan have been absorbed.

Step 7

While tossing the pasta constantly, slowly start pouring the egg mixture into the skillet, pouring into the center over the pasta and not around the edges.

Step 8

Return the guanciale to the pan. Turn the heat on to the lowest setting and cook, tossing constantly, until the sauce starts to thicken and coats the pasta, 1 to 2 minutes. Make sure to move the skillet around so any hot spots on the burner don’t scramble the eggs. Remove the pan from the heat.

Step 9

Taste and season with more kosher salt and black pepper as needed. Transfer to a large or individual serving bowls and serve immediately with more grated Pecorino and a few grinds of pepper on top if desired.