Cook the Guanciale: Cut the guanciale into small pieces. Place it in a skillet over medium heat and cook for 2 to 3 minutes, stirring occasionally until it's crispy or cooked to your liking. Remove from heat and set aside.
7 oz guanciale
Prepare the Egg and Cheese Mixture: In a mixing bowl, combine the eggs, grated Pecorino Romano cheese, and freshly ground black pepper. Whisk together until smooth and creamy. Set aside.
4 whole eggs, 1 cup plus 1 tablespoon grated Pecorino Romano cheese, Freshly ground black pepper
Boil the Spaghetti: Fill a large pot with water and bring it to a boil. Add salt to the water, then add the spaghetti. Cook according to the package instructions until al dente.
12 oz spaghetti, Salt
Combine Pasta with Guanciale: Using tongs or a pasta spoon, transfer the cooked spaghetti from the pot to the skillet with the guanciale. Toss over medium heat to combine the flavors.
Add the Egg and Cheese Sauce: Turn off the heat. Quickly pour the egg and cheese mixture over the hot pasta in the skillet. Stir rapidly to coat the spaghetti evenly. The heat from the pasta will cook the eggs gently, creating a creamy sauce without scrambling.
Adjust the Sauce and Serve: If the sauce is too thick, stir in a little of the reserved pasta water to thin it out. If it's too thin, add more grated cheese. Serve immediately, garnished with extra grated Pecorino Romano cheese and freshly ground black pepper if desired.