To prepare the caponata, fry off the aubergine and drain on paper towel.
In a seperate saucepan, heat with oil and sauté onions and celery until they begin to colour and soften.
Add the capers, tomato sauce, aubergine and olives, and simmer for 5 minutes.
Add the vinegar and sugar to taste and cook for a further 5 minutes.
Check the seasoning again.
Allow to cool and serve at room temperature, topped with toasted pine nuts on top of Crostini
