first fry the aubergine in a large frying pan, turning often. make sure it's golden brown on all sides and well cooked through.
in a sauce pan, saute the onion and celery in 1 tbsp olive oil until soft but not coloured (at leats 5 minutes).
add the tomatoes and cook for 10 minutes, stirring occassionaly.
add the capers, olives, sugar, salt and vinegar and cook for 15 minutes.
add the aubergine. adjust seasoning and leave to stand for at least 30 minutes or overnight before serving.
serve warm or at room temperature with ricotta and chopped fresh parsley.