Whisk 8 fresh medium-large egg yolks (no egg whites) in a bowl, then add the pecorino cheese and pepper and mix well.
Drain the pasta and pour it in the frying pan with the guanciale. Cook for 1 minute.
Remove the frying pan from the heat and pour in the egg mixture. Stir quickly and constantly until it reaches a creamy mixture, add cooking water previously preserved if necessary. Add pepper and a sprinkle of pecorino in the end.