Browsing the web, you'll run across many cooking sites offering the "original" recipe for carbonara. They flood you with hundreds of tips, but almost all focus on the three ingredients considered canonical: eggs, guanciale and pecorino, plus an abundant sprinkling of pepper.
Many also seem to enjoy narrowing the field even further. The guanciale has to be from Amatrice (because carbonara and amatriciana, as we know, are kissing...