Also known as a spanish omelet, this tasty dish can be prepared the night before and will provide all the carbohydrates and protein you need to make it through the rest of your workday.
1 tablespoon extra-virgin olive oil
1 small Yukon Gold potato (about 1/4 pound/115 grams), peeled, quartered and cut into 1/8-inch (3-millimeter) slices
1/2 medium yellow onion, halved and thinly sliced
Salt and freshly ground pepper
1 tablespoon unsalted butter
4 large eggs
Pinch of nutmeg
In a 10-inch (25-centimeter) nonstick skillet, heat the oil over medium heat. Add the potato and onion and season generously with salt and pepper. Cook, stirring occasionally, until the potatoes and onions are translucent and very tender, 8 to 10 minutes. Transfer the potatoes and onions to a bowl and wipe the skillet clean.
In the same skillet, melt the butter over medium-low heat. Beat the eggs with the nutmeg and pour them into the pan. Cook undisturbed for 1 minute, then spread the potato and onion mixture over half of the eggs in an even layer. Continue cooking until the edges are set and the top is almost set but still moist, 5 to 7 minutes.
Using a spatula, fold the omelet in half to cover the filling, and then fold in half again. Remove the torta from the skillet and let it cool, then cut it in half and pack for lunch.