Optional: Chopped fresh parsley, basil, or other herbs for topping
Place your eggs on the counter (in a safe place!) so they can come to room temperature.
Set a pot of salted water to boil. While it heats, fry the pancetta/guanciale/bacon over medium low heat until crispy; add a little olive oil to the pan if needed. Keep the juices! Set aside to cool.
When the water comes to a boil, add pasta. Right before it’s done, set aside a cup or so of salty pasta water. Cook until al dente and drain.
While the pasta cooks, crack eggs in a bowl and add about a quarter cup of reserved hot water. Quickly beat until the color is uniform (this is tempering, cooking the eggs a bit without scrambling). Stir in the now-cool pancetta, cheese, and pepper.
Drain the pasta. Return to the pot and, as quickly as you can, toss in the egg mixture. Keep tossing until the noodles are well coated and the egg seems disinclined to scramble.
Add more pepper and Pecorino to taste. Served topped with a sprinkle of cheese and fresh herbs.