Place each sweet potato on a piece of foil, drizzle with olive oil, season well and wrap up. Place the foil packages in the coals of a medium-hot fire and roast for 40 minutes, or until tender.
In the meantime, drizzle the kale leaves with oil, season well and place on a grid over the coals. Turn often to prevent them from burning. Roast for 5-8 minutes or until crispy. Set aside.
Mix the yoghurt with the spices and seasoning.
Score the sweet potatoes with a knife then top with the yoghurt, thinly sliced beetroots, crispy kale, seeds and mint.