Carbonara sauce is a sauce for pasta.
The basic ingredients in Carbonara Sauce are eggs, cheese and pork fat. Throughout most of Italy pancetta is used as the pork element, except in Rome, where pork jowl (“Guancial”) is sometimes used.
If you use pancetta, bear in mind that pancetta is much saltier than bacon, so you may want to add any salt at the very end to see how much is actually needed.
There are actually some pretty strong opinions about how Carbonara originated, and each camp of opinion tend to discount all the others. It’s important to them, you see, because how it originated backs their opinions about whether bacon or pancetta should be used.
Some argue that Carbonara didn’t originate until World War II, with the bacon from American soldiers’ supplies. Certainly, there is no real mention of it in Italian cookbooks before the 1960s, and it didn’t become known in America until after World War II, popularized both by returning soldiers from Italy and Italian immigrants.
As for the name, there are conflicting theories as well. One holds that the charcoal diggers (i carbonari) would take dry pasta, pancetta and cheese with them on their digs up in the mountains. Those ingredients would travel well, and eggs could be procured along the way. The dish is named after these “carbonari”. This version also has the benefit of backing up the pancetta school of thought.
More likely, though, the name is related to the ground black pepper sprinkled on top, which could look like coal dust.
In any event, while the amateurs argue, most professional food writers (such as Anna del Conte and Julia della Croce) just say “nobody really knows”, but that somehow the dish appeared and it became popular in Italy after WWII.