The Pope’s Eye is a small round piece of fat found in the leg or shoulder of mutton. You find it as you are carving slices in towards the bone.
Most people advise that you shouldn’t cut into and serve it; others, though, ask for it, as they consider it a flavourful treat.
Literature & Lore
“The Pope’s eye (as it is commonly called) is a choice bit both in Leg and Shoulder.” Hannah Woolley. The Gentlewomans Companion. London. 1673.