- ¾ cup extra virgin olive oil
- 1 small onion, halved through the root end and thinly sliced
- 1½ teaspoons Spanish smoked paprika or sweet paprika, plus additional for garnish (see Note)
- 2 large russet potatoes (about 10 ounces each), peeled and halved lengthwise
- Kosher salt, as needed
- 8 large eggs, as fresh as possible
- ½ teaspoon sugar
- Add 3 tablespoons of the olive oil, the onion, and the paprika to an 8- or 9-inch nonstick skillet and place over medium heat. Cook gently for 4 minutes, stirring occasionally, without coloring the onion. Add the remaining oil and let it warm. Meanwhile, slice the potatoes crosswise into very thin slices, a bit less than 1/8-inch thick. Add them to the onion and oil mixture in handfuls, spreading out each addition and sprinkling them with salt as you go. Cook the potatoes over medium-low heat for about 20 minutes or until they are just tender, gently stirring them to both separate the slices and bathe them in the flavored oil. You don’t want them to brown, so adjust the heat as necessary.
- When the potatoes are just tender, remove the pan from the heat and allow potatoes to rest in the oil for 4 to 5 minutes. Drain potatoes in a colander set over a bowl. Reserve 2 tablespoons of oil, and either discard the rest or save it for another use.
- Beat the eggs with the sugar and a pinch of salt in a large bowl. Transfer the still-warm potatoes and onion to the bowl of eggs. Combine thoroughly and let the mixture rest for 30 minutes. Wipe the skillet clean, and return the 2 tablespoons reserved oil to the skillet.
- Place the skillet over medium-high heat until the oil is hot but not smoking. Add the egg and potato mixture, shaking and swirling the skillet for about 25 seconds. Reduce the heat to medium-low, distribute the potatoes evenly in the skillet, and cook until the bottom is light golden in color, and the top is just beginning to set, about 6 to 8 minutes. Remove the skillet from the heat and invert a large plate over the tortilla. Then, in one quick motion, turn the plate and skillet over so that the tortilla falls on the plate. Very quickly slide the tortilla into the skillet and continue to cook over medium heat until the eggs are just set in the middle but still moist, about 3 minutes more. Remove to a plate.
- Let the tortilla come to room temperature. Sprinkle with additional paprika just before serving. To serve, either cut the tortilla into wedges, or make diagonal cross-cuts so that many bite-sized pieces are created. If you’ve gone the latter route, stick toothpicks into each piece.