Happy hour in Venice is best spent at one of the city’s bacari, cozy, traditional wine bars tucked within the winding streets and pedestrian walkways. Here, the after-work crowd chats over wine and small plates of appetizers known as cichéti. Among these will be sarde in saor, or sweet and sour sardines, a unique reflection of Venice’s past as a hub for world trade.

Sarde in saor is made by coating sardines with flour, frying them, and then marinating them in layers of onion and vinegar. Frying and marinating food in a sweet and sour sauce—known as saor—was a common method of preservation in medieval Venice. It proved especially useful to sailors, who needed their daily catch to stay edible over long sea voyages.

Venetian cuisine also reflected the region’s penchant for Middle Eastern and North African spices. Thus, sarde in saor often included pine nuts and raisins, which are still added to the dish today. This unique mix of cooking methods and ingredients makes sarde in saor both bitingly sour and delicately sweet, an intensity that chefs sometimes balance by serving the dish with grilled polenta squares.

Once a year, sarde in saor is elevated from humble tavern food to a festive dish. On the third Sunday of July, Venice celebrates the Festa del Redentore, which commemorates the end of a plague that swept through the city in the 1500s. Before a massive nighttime fireworks display, locals spend the day decorating their boats and terraces, and enjoying sarde in saor with prosecco.