Bring a large pot of salted water to a boil and cook spaghetti according to package instructions until al dente. Drain, reserving 1 cup of pasta water.
In a bowl, whisk together eggs, grated Parmesan cheese, black pepper, and salt until smooth.
Add cooked spaghetti to the skillet with pancetta; remove from heat. Slowly pour egg mixture over the pasta, tossing quickly to create a creamy sauce. Add reserved pasta water as needed for consistency.
Serve immediately with additional Parmesan and black pepper if desired.
Notes
This recipe is best enjoyed fresh and hot. Avoid reheating as it can cause the sauce to separate.