Potato and Onion Tortilla

This deep-set omelette with sliced potatoes and onions is the best-known Spanish tortilla and makes a deliciously simple meal when served with leafy salad and crusty bread. Tortilla are often made with a variety of ingredients-chopped red or yellow (bell) peppers, cooked peas, corn, or grated cheddar or Gruyère cheese can all be added to