[Sca-cooks] I mentioned an Italian cured hog jowl...

[Phil Troy / G. Tacitus Adamantius]

...it is called guanciale, and is highly flavored and, because of its 
gelatin content, remains moist and tender through virtually any 
cooking process.

Over time, pancetta (cured belly, like American streaky bacon) has 
become a common substitute, and for that, prosciutto or bacon are 
often substituted (especially in the US, with some of the interesting 
import laws we've had).

Adamantius