2Place the guanciale in a cold frying pan over medium heat; it will release its fat and fry in it.
3Set aside the guanciale and save the fat.
4Cook 150 grams of spaghetti in boiling salted water.
5In a bowl, add four egg yolks, 30 grams of grated Grana Padano, and 20 grams of Pecorino Romano. You can use 50 grams of one cheese or substitute it with Parmesan.
6Add freshly ground black pepper and mix.
7Reserve 200 milliliters of the pasta cooking water and drain the spaghetti.
8Do not throw away the water, we're going to make a bain-marie.
9Place the egg bowl over the boiling water and add the guanciale fat.
10Emulsify the mixture and add a little water, stirring to create an airy and light sauce.
11Once the spaghetti is cooked, mix it with the sauce, adding water little by little until the creamy sauce is formed.
12Serve, garnish with Pecorino Romano, guanciale, and freshly ground black pepper.