Cook the pasta in plenty of boiling salted water;
Cut the guanciale or pancetta into small pieces;
In a pan, brown the guanciale pieces over high heat until crispy but not burnt;
Set the guanciale or pancetta aside and remove some of the fat with paper towels as the guanciale or pancetta will get crispier and will be tastier without all the oil.
Cook the fat in the pan over medium-high heat and add a scoop of pasta cooking water;
Simmer for a few seconds and add some ground pepper; then remove it from the heat;
Two minutes before the end time stated on the pasta cooking instructions, drain the pasta with a mesh skimmer and add it directly to the pan with the guanciale fat along with a few scoops of pasta cooking water, which is rich in starch and makes the pasta creamier;
Toss the pasta with the sauce;
Add a scoop of pasta cooking water and sauté it over high heat; add half of the grated Pecorino, a little at a time;
Sprinkle the mix with ground pepper and add another scoop of water;
Add most of the remaining Pecorino; toss well until the pasta is evenly coated. Don’t worry if it doesn’t melt instantly; stir well with a wooden spoon. The heat of the pan and the starch of the water will turn the pecorino into a smooth delicious sauce.
Garnish the pasta with the guanciale pieces and the remaining Pecorino and more pepper; serve it very hot.