Ground black pepper. Cut the aubergine into 1 cm slices. Cut the courgettes diagonally into 1 cm 1 cm slices. Cut the peppers into large slices. Mix the oil, vinegar, garlic, oregano and black pepper in a large bowl. Add the vegetables. Cover with the mixture and leave to marinade for at least one hour. Cook the vegetables on a barbecue or under a hot grill until just tender, basting frequently.