Fatback is the thick layer of solid fat from a pig's back, sold fresh or lightly cured but without the heavy salt cure of salt pork. The two are often used interchangeably at the counter but are not the same product: salt pork is brined firm and salty, while fatback stays soft and mild, closer to fresh pork fat.
It is prized for its neutral, rich flavor and gelatinous texture, which melts as it cooks. Fatback is a workhorse in charcuterie, ground into sausage for moisture and mouthfeel, rendered for cooking fat, or cut into thin lardons to enrich braises, stews, and greens. It also shows up in some pastry doughs, where it produces an especially tender, flaky crumb.