Classic Spanish Tortilla de Patatas

Peel the potatoes and onion. Slice the potatoes into thin rounds (about 1/8 inch thick) and thinly slice the onion.

In a large skillet, heat the olive oil over medium heat. Add the potatoes and onion, ensuring they are mostly submerged in the oil. Cook gently, stirring occasionally, until the potatoes are very tender and the onion is translucent and softened (about 20-25 minutes). Do not brown them.

Remove the potatoes and onion from the skillet with a slotted spoon and drain well, reserving about 2 tablespoons of the olive oil in the skillet.

In a large bowl, whisk the eggs with salt and pepper. Add the drained potatoes and onion to the bowl and mix well to combine.

Heat the reserved olive oil in the skillet over medium-low heat. Pour the egg and potato mixture into the skillet, spreading it evenly.

Cook for about 8-10 minutes, or until the bottom is set and lightly golden. Use a spatula to loosen the edges of the tortilla from the skillet.

Place a large plate over the skillet and carefully flip the tortilla onto the plate. Add a little more olive oil to the skillet if needed, then slide the tortilla back into the skillet, uncooked side down.

Cook for another 5-7 minutes, or until the second side is set and lightly golden. The center should still be slightly soft.

Slide the tortilla onto a serving plate. Let it cool slightly before slicing into wedges and serving. Enjoy warm or at room temperature.