Breakfast, brunch or dinner -- this colorful meat-free frittata is a 30-minute meal that tastes nutritiously delicious any time.
Preheat broiler. In a medium bowl, whisk together eggs, salt, pepper and nutmeg; set aside.
In a large ovenproof skillet, heat oil over medium-high heat. Add sweet potato, onion, and chard stems. Cook and stir 4 minutes. Add chard leaves; cook and stir 2 minutes.
Add egg mixture to skillet. Cook over medium heat. As mixture sets, run a spatula round edge of skillet, lifting egg mixture so uncooked portion flows underneath. Continue cooking and lifting until almost set (surface will be moist). Sprinkle with cheese.
Place skillet under broiler 4 to 5 inches from the heat. Broil for 1 to 2 minutes or until top is just set and cheese melts.