Creating Spaghetti Carbonara is straightforward if you follow these steps:

1. Boil the Pasta: Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package instructions until al dente.
2. Prepare the Sauce: In a mixing bowl, whisk together the eggs, Pecorino Romano, and Parmigiano-Reggiano until well combined. Add a generous amount of black pepper.
3. Cook the Pancetta: In a large skillet over medium heat, add the diced pancetta or guanciale. Cook until crispy, about 5-7 minutes.
4. Reserve Pasta Water: Before draining the pasta, reserve about 1 cup of the pasta water.
5. Combine Pasta and Pancetta: Once the spaghetti is cooked, drain it and immediately add it to the skillet with the pancetta. Toss to combine.
6. Add Egg Mixture: Remove the skillet from heat. Quickly pour the egg and cheese mixture over the hot pasta, tossing vigorously to create a creamy sauce. Add reserved pasta water as needed to achieve desired consistency.
7. Season: Taste and season with additional salt and black pepper if needed.
8. Serve: Plate the pasta and sprinkle with extra Pecorino Romano and chopped parsley if desired.

These steps will guide you in creating this incredible dish effortlessly.