1. Preheat the oven to 200°C. Arrange the sweet potato on a baking tray, season with salt and sprinkle with olive oil. Roast for 25 minutes or until just tender. Now brush the slices with the chipotle sauce and place under the grill for about 5 minutes; turn the slices over, brush again with the remaining sauce and grill for another 5 minutes or until all the slices are caramelised and golden-brown.