Put a large pot of water on to boil for the pasta. Salt the water well when it is almost boiling.
While the water is heating, slice the guanciale into strips.
Heat a large saucepan (which can accomodate a pound of pasta) over medium heat, then add the guanciale strips (there’s no need to add oil.)
While the guanciale is frying, butta la pasta (throw in the pasta!) Stir well, lower the heat when it starts boiling again, and cook according to the directions on the packet.
When the guanciale is golden brown and starting to crisp, turn up the heat and add the tomatoes/passata and stir well.
Add the salt and stir again. Keep stirring while keeping the sauce simmering quickly.
When the sauce has reduced to a good consistency for pasta, taste it for salt and add the pepper, as desired and turn off the heat. This will only take 5 to 8 minutes, depending on the pan you use and how hight the heat is. Do not use a deep pot.
When the pasta is almost al dente, drain it and add it to the sauce, but RESERVE THE PASTA WATER. Gently mix the sauce and pasta together.
Gently mix the sauce and pasta together. Add in the grated Pecorino Romano, DOP and mix again until well combined.
Plate into five bowls immediately. Sprinkle with more cheese and serve.