As anyone who’s visited Florida knows, the state’s sweet calling card is Key lime pie. But Key lime’s cousin—sour orange pie—is not nearly as famous in the Sunshine State. And yet, their recipes are almost identical. Both have a graham-cracker crust topped with a tangy, condensed milk–based custard. The only real difference is the fruit that's supplying each pie’s signature flavor. The story of how one pie was catapulted into the spotlight, while another remained an obscure, though beloved, regional specialty is one of misadventures, clever marketing, and a fruit’s inability to shake its bitter reputation.