Ms. Villegas Becerril's book, "El Libro del Salmorejo: Historia de un viaje milenario" traces the soup's heritage and its incarnations on the way to Andalusia from the Middle East, before the tomato arrived from the New World sometime around 1500.

WSJ: Salmorejo the Way Mama Makes It

"People who eat it in Andalusia recognize the finesse of salmorejo, which can be present at simple restaurants and, at the same time, be part of the haute cuisine, " says Almudena Villegas Becerril, an author and food consultant based in Cordoba, who wrote a history of salmorejo that was published in 2010.

WSJ: Salmorejo the Way Mama Makes It