Two fall produce favorites are paired here in a frittata that’s bursting with color, flavor, and texture. Crumbled goat cheese adds a creamy tang, but you could substitute any other type of grated or crumbled cheese.
1. Preheat oven to 400°F. Place sweet potato pieces in medium microwave-safe bowl. Add 1/2 cup water, cover, and microwave on high power 5 minutes, or until tender. Drain.
2. Meanwhile, whisk together eggs, mustard, and vinegar; season with salt and pepper, if desired.
3. Coat large ovenproof nonstick skillet with cooking spray. Add oil, and place over medium-high heat. Add onion, and sauté 3 minutes, or until onion begins to soften. Add kale, and cook 2 minutes, or until kale is wilted but still bright green. Add sweet potato, and toss to blend, arranging vegetables over bottom of skillet.
4. Carefully pour eggs over top without displacing vegetables. Cook 3 minutes, or just until bottom of frittata is set.
5. Transfer skillet to oven. Bake 10 minutes, or until frittata is set in center.
6. Using heat-proof spatula, loosen frittata from skillet, and slide out onto platter. Sprinkle with cheese; let stand 1 to 2 minutes to soften cheese. Cut frittata into 4 wedges, and serve.