Heat the oil in a non-stick frying pan. Sauté the kale for approx. 3 mins., add the sweet potato and cook for approx. 2 mins., season.
Mix the vegetables, feta and eggs in a bowl. Heat the oil in the same frying pan. Pour the mixture back into the pan. Cover and leave to solidify over a low heat for approx. 20 mins. Top with the reserved feta.