Step 1: Cook the Pasta

1. Bring a large pot of water to a boil and add 1 teaspoon of salt.
2. Add the spaghetti and cook until al dente, following package instructions (typically 8-10 minutes). Reserve 1 cup of pasta water before draining the pasta.

Step 2: Prepare the Sauce

1. In a medium mixing bowl, whisk together the eggs, egg yolk, grated Pecorino Romano cheese, and freshly ground black pepper until smooth and creamy. Set aside.

Step 3: Cook the Guanciale

1. Heat a large skillet over medium heat. Add the guanciale and cook for 5-7 minutes, stirring occasionally, until the fat renders and the guanciale becomes golden and crispy.
2. Remove the skillet from heat and let it cool slightly to prevent the eggs from scrambling when added later.

Step 4: Combine Pasta with Guanciale

1. Transfer the drained pasta directly into the skillet with the guanciale, tossing to coat the spaghetti in the rendered fat.
2. Gradually add a few tablespoons of reserved pasta water to the skillet, tossing the pasta to loosen it and create a light sauce.

Step 5: Create the Carbonara Sauce

1. Remove the skillet from heat to prevent overheating. Slowly pour the egg mixture over the pasta, tossing continuously to coat the spaghetti in a creamy sauce. The residual heat from the pasta will cook the eggs gently, creating a silky texture.
2. Add additional reserved pasta water, 1 tablespoon at a time, if the sauce needs thinning.

Step 6: Plate and Serve

1. Divide the Carbonara among serving plates or bowls. Top with extra grated Pecorino Romano and a generous crack of black pepper.
2. Serve immediately while hot and creamy.