Prepare the Potatoes and Onions: Cut the peeled potatoes and onion into ⅛-inch thick slices.
Make the Egg Mixture: Whisk together the eggs, ½ teaspoon of the salt, black pepper, and a pinch of cayenne.
Cook the Potatoes and Onions: Heat olive oil in a large non-stick pan, add the sliced potatoes, onions, and remaining salt, and cook for about 20 minutes.
Combine and Rest: Fold the cooked potatoes and onions into the egg mixture and let it stand for 5-10 minutes.
Cook the Tortilla: Heat olive oil in a non-stick pan, pour in the egg and potato mixture, and cook for about 4 minutes.
Flip the Tortilla: Slide the partially cooked tortilla onto a plate, invert it, and return it to the pan.
Finish Cooking: Cook uncovered for about 2 more minutes until fully set.
Serve and Enjoy: Transfer to a serving plate and serve hot, warm, or at room temperature.
