Mix together the olive oil, ginger, sugar, soy sauce and lime juice in a bowl. Add the vegetables, including the onions, and turn in the dressing until evenly coated. Scatter into a shallow roasting tin or ovenproof dish. Place on the lower rack of the halogen oven.
Set the temperature to 250°C (482°F) and cook for 15 minutes. Add the garlic and toss the vegetables together. Cook for a further 15 minutes or until caramelized. Serve with roast or grilled chicken, pork or duck.