While a lot of us believe that Guanciale is from Rome, we are wrong. It definitely comes from Abruzzo, specifically from a place called Amatrice, near L'Aquila.
Despites our profuse research, we haven't been able to trace the origins of this important cured meat. What we know is that it is broadly used throughout Italy in a variety of recipes that make it the King of the Italian cuisine.
As previously mentioned under the Pancetta section, Guanciale is not to be confused as they are different meats. Nevertheless, in Australia, it's not always easy to find Guanciale and it can be replaced with Pancetta in some recipes.
The most famous recipe with Guanciale is the pasta Bucatini all'Amatriciana (from Amatrice the place where this product originates), but if you want to try something simpler, just add it to give flavour to any of your cooked veggies and you'll taste the difference!
Like pancetta, it can last for a very long time. Even if it's a non cooked product, it can be used to make other cooked salumi like Cotechino or to make the filling of chicken and turkey.