Tortilla Española

This is the most authentic and popular tapa from spain. It is the classic tapa, prepared all over Spain. You can eat Tortilla Española hot or warm.

Ingredients:
1/2 cup plus 2 to 3 Tbs. olive oil
2 lb. baking potatoes, peeled and sliced 1/4 inch thick
Salt to taste and fresh ground pepper is optional
2 yellow onions, thinly sliced (optional)
6 eggs
Chopped fresh flat-leaf parsley for garnish

Directions:
In a large nonstick fry pan over low heat, warm the 1/2 cup olive oil. Add half of the potato slices and fry, turning occasionally, until tender but not browned, 15 to 20 minutes.
Transfer to a plate and season with salt and pepper. Repeat with the remaining potato slices. Leave the oil in the pan.In another fry pan over medium heat, warm the 2 to 3 Tbs. olive oil.
Add the onions and fry until soft and golden, about 15 minutes. Remove from the heat and let cool a bit.
In a large bowl, whisk the eggs until blended. Mix in the onions.
Season with salt and pepper. Fold in the potatoes. Heat the oil remaining in the large pan over low heat and pour in the egg mixture.
Cook until the bottom is set and golden, 8 to 10 minutes. Invert a plate on top of the pan, invert the pan and plate together, and lift off the pan.
Slide the omelette back into the pan and return to low heat.
Cook until the other side is set, about 4 minutes.
Slide the omelette onto a plate, garnish with parsley and cut into squares before serving.