This simple yet classic potato and onion 'omelette' is popular throughout Spain, and is one of my very favorite things to eat. Perfect with a side salad. Tortilla Espanola or tortilla de patatas is a dish with simple delicate flavors you will love.
In a large skillet or Dutch oven heat oil on medium heat uncovered. (Make sure the oil does not get overly hot because olive oil is a low temperature oil. Too much heat destroys the phenols in the oil.)
Allow to cook until both potatoes and onions are tender. This should take about 10-12 minutes. You want the potatoes to be soft, but not fall apart. Every 3 minutes or some take a spatula and move the mixture from the bottom over the to to keep it from browning on the bottom.
Once the potato and onions are cooked, place a bowl with a colander on top. Using a slotted spoon move the potatoes and onions to the colander allow them to drain. (The bowl below will catch the oil).
In a large bowl, combine the beaten eggs and add the potato and onion mixture. Add the salt.
Let the eggs soak into to potato onion mixture for 10 minutes.
Heat your skillet, add 2 Tbsp of the oil drippings to the pan and pour the mixture in. Cover and cook for about 8-10 minutes. Check the color of the bottom with a spatula for a nice brown color.
Remove the cover and place an upside down plate over the tortilla and flip onto a large flat plate. Use grill gloves or oven mitts to avoid getting burned. Slide the tortilla back into pan and cook the other side for an additional 8 minutes.
Slide onto large plate and serve.