Bring a large pot of salted water to a boil. Add the spaghetti and cook until al dente, according to package instructions. Reserve about 1 cup of the pasta water, then drain the spaghetti.
While the pasta is cooking, cut the pancetta into small cubes. In a large pan over medium heat, cook the pancetta until it is crispy and golden, about 5-7 minutes. Remove from heat.
In a bowl, beat together the eggs and finely grated Pecorino Romano cheese until well combined. Add a generous amount of black pepper.
Add the hot drained spaghetti to the pan with the pancetta. Pour the egg and cheese mixture over the spaghetti, and quickly toss together to coat the pasta evenly. Add reserved pasta water gradually, if needed, to achieve a creamy consistency.
Serve immediately with additional grated Pecorino Romano and black pepper on top, if desired.