Arrgh, Maggie! No onion, no garlic, no oil, no parsley! You can use pecorino, Parmesan or a mixture. I wouldn't add salt as there's salt in the bacon, cheese and pasta water, and loads of black pepper is essential. My infallible (honest!) guide to carbonara is the late-lamented Antonio Carluccio's YouTube. It doesn't get better. Ideally we should use guancale, the cured pig's cheek, but I can't get that round here. Pancetta is great as long as it's in cubes, not thin strips, but I use unsmoked bacon lardons and I get all the fat I need by dry-frying them for the ten or twelve minutes that the spaghetti takes. All I'm saying is that that's what I do, as does Antonio, and if you ignore all this and carry on with all those extra ingredients I'm sure that it'll be delicious. But no true Italian would call it carbonara!