This is a great recipe to make when you have friends over, since you can make it in advance and just have it ready to go. It also works well to take to a picnic. To add some color to it, I added some purple potatoes to the mix. You can make this tortilla two ways. You can boil the potatoes and then place them in the skillet with the eggs, or you can fry the potatoes first and then mix them with the eggs. I prefer to do it the traditional way by frying them first. It has more flavor and it is worth it. Usually served as an appetizer, I normally have it for dinner with some salad.
1 kilo of potatoes for frying (I included some purple potatoes for contrast), thinly sliced
1 big white onion, thinly sliced
Vegetable oil for frying
Preheat the oven to 180C/350F.
Add about 3 tablespoons of vegetable oil to a cast iron skillet over medium heat. Add the onions and cook them for about 4 minutes. Stir from time to time. Then remove them from the pan, place on a bowl and set aside.
Add more vegetable oil to the pan and fry the sliced potatoes in batches. They just need to be pan-fried for about 5 minutes per batch. Remove the potatoes from the pan, trying to get rid of most of the oil. Place the fried potatoes in the bowl with the onions and season with salt and pepper.
In another bowl, whisk the eggs with some salt and pepper.
Get rid of most of the oil from the skillet, it just needs to be lightly coated. Place the potatoes and onions in the pan. Pour the whisked eggs and cook on low heat for 5 minutes.
After the 5 minutes are up, place the skillet in the preheated oven and bake for 20 minutes.
You can allow the tortilla to cool down before slicing it, or just eat it warm. I prefer the latter one.