Bring a large pot of salted water to a boil.
Add spaghetti and cook according to package instructions until al dente.
While pasta cooks, heat a pan over medium heat and add diced pancetta.
Cook until crispy, then remove from heat and set aside.
In a bowl, whisk together the eggs, Pecorino Romano, and Parmesan until well combined.
Once the pasta is ready, reserve a cup of pasta water and drain the rest.
Add hot pasta to the pan with pancetta, tossing to combine.
Remove from heat and quickly stir in the egg mixture, adding reserved pasta water as needed for creaminess.
Season generously with freshly ground black pepper.
Serve immediately, garnished with extra cheese and pepper if desired.