Step 1

Bring a large pot of salted water to a boil over medium-high heat.

Step 2

Meanwhile, make the sauce. Whisk 4 large egg yolks, 2 ounces grated Pecorino Romano cheese, and 1/2 teaspoon coarsely ground black pepper together in a medium heatproof bowl.

Step 3

Heat 2 teaspoons olive oil in a large Dutch oven or high-sided skillet over medium-low heat until shimmering. Add 4 ounces chopped guanciale and spread into a single layer. Cook, stirring occasionally, until browned and crisp, 6 to 10 minutes. Use a slotted spoon to transfer the guanciale to a small bowl.

Step 4

Turn off the heat. Transfer 1 tablespoon of the fat in the pan to the egg mixture and whisk to combine. Remove all but 1 tablespoon of the remaining fat from the pan (discard or reserve any remaining fat for another use).

Step 5

Return the pan to medium-high heat. Add 1 finely chopped medium yellow onion and 2 finely chopped garlic cloves. Cook, stirring frequently, until the onions are slightly softened but not browned, about 3 minutes. Add 12 ounces uncooked Italian sausage. Cook, breaking up the meat with a wooden spoon into bite-sized pieces, until browned and cooked through, 6 to 8 minutes.

Step 6

Add 2 tablespoons tomato paste and cook, stirring often, until lightly toasted and darkened in color, about 1 minute. Reduce the heat to medium-low. Add 1 (28-ounce) can puréed tomatoes, 1 tablespoon Calabrian chili paste if using, and 1/4 teaspoon red pepper flakes. Stir to combine, scraping up any browned bits from the bottom of the pan.

Step 7

Partially cover and simmer, stirring occasionally, until the sauce is slightly thickened, about 10 minutes. Meanwhile, add 1 pound dried rigatoni to the boiling water. Cook according to package directions until the pasta is just al dente, 10 to 13 minutes. Reserve 1 cup of the pasta cooking water, then drain the pasta.

Step 8

When the sauce is ready, turn off the heat. Add the pasta and guanciale, and toss to coat.

Step 9

While whisking constantly, slowly pour 1/4 cup of the pasta cooking water into the egg mixture. While stirring constantly, slowly pour the egg mixture into the pasta. Thin the sauce out with more pasta water as needed. Taste and season with kosher salt as needed. Serve topped with more grated cheese and black pepper.