Originally caponata was always made with fish but in the hands of the poor, who couldn’t afford fish, aubergines (eggplants) were used instead. Nowadays, it is eaten with both. It can be made a couple of days in advance and kept in the fridge. In fact, the flavour of caponata is always better a day or two after it’s made, but be sure to bring it to room temperature before using.
We use our griddle pan for cooking the fish as I like the visual effect of the black lines on the fish and the fact that the fat drains away into the grooves of the pan. However, a hot grill in the oven or a rack over a barbecue work just as well. Sardines or sea bass or bream are ideal cooked in this way too, and the jewel-like sweet and sour caponata is the perfect foil for all types of fish.