1.Place eggplant in sieve or colander; sprinkle all over with salt, then stand sieve over sink or large bowl for 15 minutes. Rinse eggplant well under cold running water, drain; pat dry with absorbent paper.
2.Preheat oven to 180°C (160°C fan-forced).
3.Heat oil in large non-stick frying pan; cook onion, stirring, until softened. Add eggplant and zucchini to pan; cook, stirring, until vegetables are softened.
4.Using a plate as a guide, cut a 20cm round from each pastry sheet; place rounds on oven trays. Spread equal amounts of pesto in centre of each round, leaving a 4cm border around the outside edge.
5.Divide vegetables among rounds over pesto; top each with equal amounts of cheese, tomato and basil. Using hands, turn the 4cm edge on each round over filling; brush around pastry edge with egg. Bake, uncovered, in oven about 40 minutes or until pastry is browned lightly.
Allowing the eggplant to stand a while covered with salt will help withdraw most of the vegetable’s slightly bitter juice; it also helps prevent the eggplant from absorbing too much oil when it’s cooked. Be sure to rinse the eggplant well under cold running water to remove as much of the salt as possible and to dry it thoroughly with absorbent paper before cooking it.