Bring a large pot of salted water to a boil and cook the spaghetti according to package instructions until al dente.

While the pasta is cooking, heat a large skillet over medium heat and add the diced guanciale. Cook until it becomes crispy and golden, about 5-7 minutes.

In a bowl, whisk together the eggs, grated Pecorino Romano, and a generous amount of freshly cracked black pepper until well combined.

Once the spaghetti is cooked, reserve about 1 cup of the pasta cooking water, then drain the pasta and add it directly to the skillet with the guanciale.

Remove the skillet from heat and quickly pour in the egg and cheese mixture, tossing vigorously to create a creamy sauce. If the sauce is too thick, add reserved pasta water a little at a time until desired consistency is reached.

Serve immediately, garnished with additional Pecorino Romano and black pepper.