Cut guanciale into strips, making sure each strip includes all layers of fat. Reserve a handful to sprinkle on top at the end for added crunch.

Place guanciale in a cold pan and render slowly over low heat until golden and the fat is released.

Crush canned plum tomatoes by hand in a bowl.

Add tomatoes to the pan with guanciale. Simmer for 10 minutes, stirring occasionally.

Cook spaghetti in a large pot of salted boiling water until al dente.

Drain spaghetti and add to the sauce. Toss well to coat.

Remove from heat and mix in grated Pecorino Romano.

Serve with reserved guanciale pieces on top.