1. Preheat the oven. Mix the carrot, sweet potato and onion with the olive oil, apple cider vinegar and brown sugar; season generously with salt and pepper. Arrange the vegetables in a single layer in an ovenproof dish, cover with a lid or foil and bake for 20 minutes.
2. Carefully turn the vegetables over in the dish, preheat the grill and continue roasting until cooked, with delicious caramelised bits all over. Turn over as needed.