To make pasta alla zozzona, begin by finely chopping the onion and gently sweating it in a saucepan with a drizzle of olive oil.
Once the onion is translucent, remove the sausage from its casing, crumble it, and add it to the pan along with the guanciale.
Brown the meat until the sausage has changed color and the fat begins to render.
Add the cherry tomatoes, season with salt and pepper, cover the pan, and let the sauce simmer and reduce for about 15–20 minutes.
Meanwhile, whisk the egg yolks in a bowl with a pinch of salt, freshly ground black pepper, and the grated Pecorino Romano until a thick cream forms.
Boil the pasta in salted water, drain it al dente, and transfer it directly to the pan with the sauce.
Remove the pan from the heat, pour in the egg yolk cream, and toss vigorously to combine, adding a splash of reserved pasta cooking water if necessary to achieve a silky consistency.
Stir well and transfer to serving plates. Serve the pasta alla zozzona hot, garnished with extra grated Pecorino Romano to taste.
