boil water for pasta
Place a pot filled with salted water over high heat and bring to a boil.
Place a skillet over low heat. Add guanciale or pancetta and pan-fry for 6 - 8 minutes or until crispy and golden-brown. Transfer to a paper towel to eliminate excess fat, but leave the frying fat in the pan.
Add dried chili and canned tomatoes to the same skillet and place over medium heat. Gently season with salt and pepper. Simmer for 6 - 8 minutes. While the sauce is simmering, cook the pasta al dente according to the package instructions. Make sure not to overcook the pasta as it will cook a little more with the sauce.
Add the al dente-cooked pasta to the sauce. Add 120ml (1/2 cup) of reserved pasta water. Toss and place over low heat for another 2 minutes for the pasta and sauce to combine. Remove from the heat and add half of the shredded parmesan cheese. Toss to combine, then add the rest of the cheese. Divide between plates and serve immediately.