Potato-Chard Frittata

In a large oven-proof skillet, saute 1 sliced onion for about 5 mins. Add 1 bunch chard and 1 medium potato, both thinly sliced. Cover and cook until soft, about 10 minutes. Stir in 2 cloves pressed garlic, 10 beaten eggs, 1 1/2 c. shredded cheese, 1 T. oregano, and salt to taste. Cook on medium for 5 mins then move to 375° oven and bake until the whole thing is set, about 15 mins more. Serve warm.