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

Reserve a cup of pasta water, then drain the pasta.

In a large skillet over medium heat, add the diced pancetta and cook until crispy.

In a bowl, whisk together the eggs, Parmesan, Pecorino, and black pepper until well combined.

Add the hot spaghetti to the pancetta in the skillet, tossing to coat.

Remove from heat and quickly pour the egg mixture over the spaghetti, stirring vigorously to create a creamy sauce. Add reserved pasta water as needed to achieve desired consistency.

Serve immediately with additional grated cheese and black pepper on top.