Heat 3 tablespoons of the oil in a large frying pan over a high heat. Add half of the aubergine cubes and fry until browned. Remove the aubergine from the pan and set aside. Heat another 3 tablespoons of the oil and fry the remaining aubergine. Set aside with the rest.

Heat the remaining oil in the pan. Add the onions, celery and pepper and fry over a high heat for 3–4 minutes. Add the garlic and fry for a few seconds. Return the aubergine to the pan, add the passata, olives, vinegar, capers and sugar. Season with salt and black pepper, cover with a lid and bring up to the boil. Reduce the heat and simmer gently for 20–25 minutes. Remove the lid and simmer for another 5 minutes, until the sauce has reduced and the vegetables are soft but not mushy.

Sprinkle with parsley and serve with crusty bread, couscous or as a vegetable side dish.