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

Meanwhile, heat a large skillet over medium heat. Add the diced pancetta and cook until crispy, about 5-7 minutes.

In a bowl, beat the eggs with the grated Pecorino Romano and Parmesan cheeses. Season with black pepper.

When the pasta is cooked, reserve 1/2 cup of the pasta water, then drain the pasta.

Working quickly, add the hot pasta to the skillet with the pancetta, then remove from heat. Pour the egg and cheese mixture over the pasta, stirring quickly to create a creamy sauce. Add a splash of the reserved pasta water if needed to loosen the sauce.

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