A favorite of home cooks and tapas bars in Spain, tortilla española (or tortilla de patatas) is a tender, lightly runny omelet filled with olive oil-poached potatoes. Use a fruity, robust extra-virgin olive oil for the best results. This recipe is adapted from Lalo Beltran’s at Barcelona Cooking.
- 2 cups extra-virgin olive oil, or more as needed
- 3 medium waxy potatoes, such as Kennebec or Yukon Gold (1 lb. 6 oz.), peeled, quartered, and sliced 1/8 inch thick (4 cups)
- 1 medium sweet onion, such as Figueres or Vidalia (5 oz.), peeled, quartered, and sliced 1/8 inch thick (1 cup)
- 6 large eggs
- 2 tsp. sea salt
- In a large, wide pot over medium-high heat, add the oil. Once the oil is hot, add the potatoes and onion (the oil should fully submerge the vegetables; add more if needed to do so). Cover, lower the heat to medium, and let the oil simmer until the potatoes are very tender when poked with a fork, 10–12 minutes.
- Place a metal strainer over a large heatproof bowl. Carefully strain the vegetables, reserving the oil. Set the vegetables and oil aside separately and let cool slightly.
- In a medium bowl, whisk together the eggs and salt, then gently fold in the vegetables, taking care not to break the potatoes. Set aside at room temperature and let rest for at least 5 minutes and up to 30.
- When ready to cook the tortilla, in a 10-inch cast-iron skillet over high heat, add 2 tablespoons of the reserved oil (save the rest for another use, or discard). When the oil is hot but not yet smoking, pour in the egg and vegetable mixture, then shake the skillet gently to form an even layer. Cook until the edges of the egg begin to ruffle and turn pale yellow, about 2 minutes. Run a silicone spatula along the edge of the pan to loosen the tortilla and continue cooking until the eggs begin to set at the edges, 1–2 minutes more. Invert a large heatproof plate over the egg mixture to cover (it should be slightly smaller than the skillet so it fits inside the skillet’s rim flush up against the surface of the egg). Working quickly and confidently, flip the tortilla onto the plate by inverting the skillet. Return the skillet to the heat, then slide the tortilla back in with the uncooked side facing down. Cook until the bottom of the tortilla is just set, about 1 minute more, using the spatula to tuck the top edges of the egg tidily around and under the vegetables.
- Invert the plate over the tortilla, and carefully flip the skillet to turn the tortilla out onto the plate. Let rest at room temperature for about 5 minutes, then slice into wedges and serve warm or at room temperature.