Because this pasta is quite rich, serve it in slightly smaller portions with a green vegetable or salad. Guanciale (cured pork jowl) adds savory depth and richness to this dish. If guanciale is unavailable, use the highest-quality pancetta you can find; be sure to buy a 5-ounce chunk and not presliced or prediced. Do not use bacon; its smoky flavor will overpower the dish. Passata is an uncooked tomato puree usually found near the other tomato products in the grocery store; if you're buying the Pomì brand it may be labeled “strained tomatoes.” If you cannot find passata, you can use tomato puree instead.

Slice guanciale into ¼-inch-thick strips, then cut each strip crosswise into ¼-inch pieces. Heat guanciale and oil in 10-inch nonstick skillet over medium heat, stirring frequently, until fat is rendered and guanciale is starting to brown, 4 to 6 minutes.

Add sausage and onion and cook, using wooden spoon to break meat into pieces no larger than ½ inch, until sausage is no longer pink, 8 to 10 minutes. Stir in passata; reduce heat to medium-low; and simmer, covered, stirring occasionally, until fat is fully incorporated, 2 to 4 minutes.

Meanwhile, bring 2 quarts water to boil in large pot. Add pasta and 1 teaspoon salt and cook, stirring often, until al dente. Reserve 1 cup cooking water, then drain pasta and return it to pot. Add tomato-meat sauce to pasta. Set pot over medium-low heat and stir until pasta is well coated, about 1 minute.

Whisk Pecorino, egg yolks, and pepper in medium bowl until combined. Slowly whisk ½ cup of reserved cooking water into egg yolk mixture (mixture will not be smooth). Off heat, stir egg yolk mixture into pasta until sauce looks glossy and is slightly thickened, about 1 minute. Adjust sauce consistency with remaining reserved cooking water if needed. Transfer pasta to platter and serve immediately, passing extra Pecorino separately.