Unlike the Mexican Tortilla the Spanish version is an omelette, with potatoes and some times onion. It is a simple dish, but very tasty, and is often served in slices as a tapas.
1 cup olive oil two large potato's thinly sliced, salt to taste, one large onion, thinly sliced, four large eggs
To make what in English is called a Spanish Omelette.
Cut the potato in to thin slices.
Cut the onion in to similar sized slices.
Cook the potato and onion slices in a pan until they are soft, but not brown using the olive oil.
Beat the eggs in a bowl, and add the drained cooked potato and onion.
When the potato and onion mix is thoroughly coated in egg return the mix to the hot pan, you do not need much oil as the mix still has some from the first cooking.
Using a plate big enough to cover the pan and a cloth to save you from burning yourself, turn the omelette and return to the pan cooking until both sides are golden brown and the center is set.
Serve in wedges hot or cold as a snack or with salad or chips as a meal you will enjoy this immensely
Variations on Spanish omelette or tortilla de patatas can include mushrooms and or green and red peppers or even cooked peas or white beans which would have been cooked with the potato and onion mix.
You can see the method in this video http://www.youtube.com/watch?v=EYGWGbPl0_I