Nutrition per serving may change if servings are adjusted.
1 tablespoon extra-virgin olive oil
4 all-purpose potatoes, (about 1 1/2 pounds), peeled and cut in 1/8-inch-thick slices
2 Cubanelle (sweet frying) peppers, cored, seeded, and thinly sliced
1 onion, thinly sliced
3/4 teaspoon salt
Freshly ground pepper, to taste
3 large eggs
3 large egg whites
Heat 1 1/2 teaspoons oil in a large nonstick skillet over medium-low heat. Add potatoes, peppers and onions. Season with 1/2 teaspoon of the salt and a generous grinding of pepper. Cover and cook for 15 minutes, turning the vegetables occasionally, until potatoes are tender and lightly browned. Set aside to cool slightly.
Beat eggs, egg whites, 1/4 teaspoon salt and a generous grinding of black pepper in a large bowl with a whisk or a fork. Add the cooled potato mixture and mix to thoroughly coat the vegetables with eggs. Wipe the skillet clean.
Pour the remaining 1 1/2 teaspoons oil into the skillet and heat over medium heat. Add the egg mixture, spreading the vegetables evenly across the pan. Cook for 4 to 5 minutes until the underside is browned. (It should be slightly soft in the center.) Invert a large plate over the pan and turn out the tortilla onto the plate. Slide the tortilla back into the skillet. Cook for 2 to 3 more minutes, or until the underside is brown. The tortilla should be firm but still moist. Transfer to a serving plate and and let stand a minute or two before cutting into wedges. Serve hot or at room temperature.