Guanciale is the cured, unsmoked jowl and cheek of the pig — a salt-and-pepper-rubbed, air-dried cut prized as the authentic fat of Roman cooking. Far richer and more delicately porky than belly-based pancetta, it is mostly creamy white fat veined with a single thin streak of rose-pink meat, and when diced and rendered it melts into a silky, intensely savoury fat that is the soul of carbonara, amatriciana and gricia.