The Secret to the Chang Family Ceviche? It's in the Sauce.

It all started when Fernando and Valerie Chang went searching for a taste of home. The siblings had followed their chef father, Fernando Sr., from northern Peru to Miami in 2001, and, though South Florida restaurants served ceviches and tiraditos aplenty, there were none that delivered the puckering punch they grew up eating. “The north is considered more aggressive from a seasoning standpoint,” says Fernando.

The diagnosis: American...