Sauté sweet potatoes in hot oil in a 10-inch cast iron or ovenproof nonstick skillet over medium heat 8 to 10 minutes or until potatoes are tender and golden. Add kale, onion, and garlic and cook 3 to 4 minutes or until kale is wilted and tender. Pour egg mixture evenly over vegetables, and cook 3 more minutes. Sprinkle egg mixture with feta cheese and then place skillet in oven.
3 Bake 10 to 14 minutes or until set.