It needs some adjustments but a very good start. I used Italian seasoning instead of the parsley since I didn't have any. We sauteed 3/4 of a package of mushrooms and added to the pan right before the eggs. I also added 2 cloves of garlic with the onions and potatoes and sprinkled some Parmesan cheese on the top while the eggs were setting. It's still missing a little something so next time I might add some pancetta or prosciutto. I also used a pan that wasn't non-stick - bad idea since the eggs stuck to the bottom - so next time I will definitely use non-stick.
Potato and Onion Frittata
2 Tablespoons olive oil
1 large onion, halved and thinly sliced
1 (8 ounces) baking potato, peeled and thinly sliced
1/2 Teaspoon dried rosemary, crumbled
Coarse salt and ground pepper
5 large eggs
5 large egg whites
1/2 Cup whole flat-leaf parsley leaves
1. In a medium (10-inch) nonstick broiler proof skillet, heat 1 tablespoon oil over medium heat. Add onion, potato, and rosemary; season with salt and pepper, and toss to combine.
2. Cover skillet, and cook 10 minutes; uncover. Cook, tossing mixture occasionally, until onion and potato are tender, about 5 minutes.
3. Meanwhile, in a medium bowl, whisk together eggs, egg whites, parsley leaves, 3/4 teaspoon salt, and 1/4 teaspoon pepper.
4. Heat broiler with rack set 4 inches from heat. Add remaining tablespoon oil to vegetables in skillet. Pour egg mixture into skillet.
5. Cook on stove, over low heat, lifting mixture a few times around the edges with a spatula to let egg flow underneath. Continue cooking until frittata is almost set in center, about 10 minutes.
6. Place skillet under broiler; broil until frittata is set and top is lightly golden, about 3 minutes. Run a clean spatula around edges to loosen, then slide frittata out onto a serving plate, and cut into wedges.