1.Spray eggplant on both sides with cooking oil; cook on a heated grill plate (or grill or barbecue) over high heat for 2 minutes on each side or until browned and tender.
2.Meanwhile, preheat grill. Place prosciutto on an oven tray lined with baking paper. Grill for about 3 minutes or until prosciutto is browned and crisp. Remove from grill; cover to keep warm. Leave grill on.
3.Meanwhile, heat half the oil in a shallow 2-litre (8-cup) flameproof baking dish over medium-high heat. Season pork; cook for 1 minute on each side or until almost cooked. Remove from heat. Remove pork from dish.
4.Slice bocconcini thinly. Add tomatoes to dish; place pork on top. Top pork with eggplant and bocconcini.
5.Place baking dish under grill; cook for about 3 minutes or until bocconcini melts and pork is cooked through.
6.To serve, spoon tomato over the pork stacks, top with prosciutto and cress; drizzle with remaining oil.