Sicily's world-famous sweet and sour agrodolce relish: fried aubergines stewed with celery, onions, tomatoes, green olives, capers, toasted pine nuts, and sweetened vinegar.
Heat 1cm olive oil in a wide skillet. Fry diced aubergines in batches until golden brown and tender. Drain on paper towels and season with a pinch of salt.
In a fresh pan with 3 tbsp olive oil, cook sliced onion for 8 minutes until soft. Add blanched celery, olives, and capers, cooking for 5 minutes. Stir in chopped tomatoes and simmer for 10 minutes.
Whisk vinegar and sugar until dissolved. Add fried aubergines and pine nuts to the skillet, pour in the vinegar-sugar mixture, and cook vigorously for 3-4 minutes until vinegar evaporates into a shiny sweet-and-sour glaze.
Remove from heat, fold in fresh basil leaves, and let cool completely. Caponata must be served at room temperature or chilled the following day for best flavor.