If you decide to use an onion in your tortilla, peel and slice it thinly.
Peel and wash your potatoes and break them into small, somewhat evenly sized pieces. (Don't work too hard at it. This is only so that they will cook at a similar rate.)
Fill your frying pan with enough extra virgin olive oil to cover the potatoes and begin to heat it over low to medium heat.
When it has warmed up, add your potatoes and fry at medium heat, stirring them to keep them from burning and sticking to the bottom of the pan. This will be easier if you use more oil than is shown in the picture, which was taken during one of my experiments looking for the best way to make a tortilla. When fried at a relatively high temperature in a lot of oil, the potatoes will get crispy on the outside and will taste a lot better. They will also be less likely to stick to the pan or fall apart.
After frying for a little while, add in the onions.
Keep cooking and stirring until the potatoes begin to brown and get tender when you prick them with a fork.
Drain the potatoes and onions from the oil, and add salt to taste. You can use a slotted spoon or a colander to help drain them. Many recipes recommend placing the potatoes and onions onto paper toweling to try to help absorb some of the oil, but I don't do that myself out of fear that it will all stick to the paper toweling. (Nor have I really seen it in practice here in Spain.) Feel free to give it a try if you like, though.
In a medium to large sized bowl, beat the eggs with a pinch of salt and then add the drained potatoes and onions, gently stirring the mixture to fully cover all of the potatoes. You should have enough eggs to be able to comfortably cover all of the potatoes and onions, but not so many that they are drowning in eggs. (See the photo for an idea of how to get them at the right level.) Beat more eggs and add them in if you need more.
Lightly grease a frying pan that is the size of what you think would hold all of your mixture to a height of an inch to an inch and a half, and warm it over medium heat.
When the pan is warm, add in your potato, onion, and egg mixture and let it slowly cook, checking for the eggs to set around the edges of your tortilla. To help move the process of cooking the tortilla through, you can stir it gently in the pan for a minute before leaving it alone to start forming its shape.
When you see the eggs starting to set, especially at the edges, try to help separate the tortilla from the pan by running a spatula around the edges and by swirling the pan a little to check to see if the tortilla has been released from the pan.
You are now ready to flip the tortilla.
To flip the tortilla, take a plate that is bigger than the size of your frying pan and place it upside down over the top of your pan.
Firmly hold the plate over the pan as you carefully flip the pan over allowing the tortilla to fall onto the plate. (You can see that I had the heat a little bit too high and mine got a little too dark on that side... not to fear, that side will be facing down when we are finished!)
Place your pan on the heat again, and carefully slide the tortilla into the pan, uncooked side down.
Cook for a couple of minutes more, long enough to finish cooking through to the center of the tortilla.
You have successfully made a Spanish tortilla, and can flip it once more, this time onto a serving plate.
Cut the tortilla and serve it! Enjoy!
Recipe printed from Oh, The Things We'll Make! Blog. https://thethingswellmake.com/authentic-spanish-tortilla-recipe/