Bring a large pot of salted water to boil
In a bowl, whisk eggs, egg yolks, and 1 cup Pecorino Romano
Cut guanciale into ¼-inch thick strips
Cook guanciale until crispy (8-10 minutes)
Cook pasta until al dente
Reserve 1½ cups pasta water
Add hot pasta to guanciale
Temper egg mixture with ½ cup pasta water
Toss pasta with egg mixture off heat
Add remaining cheese and pepper
Adjust consistency with pasta water
Serve immediately