The sweet and sour sauce is the same that is used to season the famous eggplant caponata, a delicious dish that is part of the poor kitchen (in fact in this case, slices of capone were replaced by cheaper pieces of eggplant). It is possible that the name caponata origins from the original plate capone, although there are several hypotheses about the origin of the name caponata.
1kg of fish, celery, 50gr of capers, 100 gr.of green olives, 1 onion, extra virgin olive oil, 100gr. tomato concentrate (you can also use peeled tomatoes), salt and pepper, 1 tablespoon sugar, 3 tablespoons of wine vinegar.
Recipe: Clean and cut into pieces the capone. Clean the celery and cook in boiling water. Rinse the capers. Wash, pitted and cut into pieces olives. Chop the onion. In a saucepan fry the onion in olive oil. Add the tomato concentrate diluted with a little water, chopped celery, salt and pepper, and cook in moderate flame.
While the sauce cooks, pass into flour the slices of capone and fry in a pan with olive oil hot. When they are ready, put them on a plate covered with absorbent paper. Add to the sauce, olives, capers, vinegar and sugar, cook for a few minutes, until the vinegar is evaporated. Add the fish and cook for a few minutes. This dish is better cold.