Place the onion, zucchini and pepper onto a lined oven tray, drizzle with half the dressing. Roast in a moderate oven 180°C for 20 minutes, add the tomato halves, drizzle with remaining dressing and cook a further 10 minutes
Boil, steam or microwave the beans and asparagus until just tender. Keep warm
Combine all the vegetables in a serving dish, drizzle with extra dressing and top with chopped parsley