Cook the spaghetti in a large pan of rapidly boiling salted water until al dente.
Meanwhile, heat the oil in a frying pan and gently fry pancetta/bacon until crisp. Take off the heat
In a bowl, lightly whisk the eggs with the cheese and pepper (a little pasta water may be added at this stage to help the eggs mix with the pasta later and it will bring the mixture to remove temperature reducing the risk of scrambling).
When the pasta is ready, drain and return the pasta to the pan. Add the pancetta/bacon mixture, stir through and then add the egg mixture to the pasta, stirring to coat the pasta. The mixture should form a thick creamy sauce that binds and clings to the pasta. Serve immediately with extra parmesan and freshly cracked black pepper.