In a large pan heat the oil and fry the aubergine till soft. Add the peppers, courgettes, onion and tomatoes and cook for a few minutes.
Mix the tinned tomatoes together with the water. Give it a good stir and then add all the spices and sugar. Leave on simmer heat for 1½ hours, checking the caponata doesn't go dry.
Preheat the grill. Blitz the bread and parsley in a food processor for a few seconds until you have large crumbs.
Add the lemon juice to the caponata and season well, then carefully spoon or tip the mixture into an ovenproof dish. Scatter the breadcrumb mix over the top so that it's completely covered. Add the grated Parmesan and place under a hot grill until golden and crispy. Serve with a green salad.