3-4 medium potatoes, sliced into "chips" with a mandolin
1 large onion, finely chopped
5-6 eggs
salt to taste
olive oil for frying
Heat the oil in a large frying pan. Make sure that the oil is about 1/4" deep. Fry the potatoes and onion to the oil for about 30 minutes. Stir and flip the mixture to ensure uniform done-ness. There may be some browning of the potato.
Beat the eggs in a large, heat-safe bowl. Add salt. When the potatoes and onion are soft, add them to the eggs. Make sure that the oil stays in the frying pan. Mix well.
Add the potato, onion, egg mixture to the hot frying pan. Smooth it out so it is the same thickness all across the area of the tortilla. Let it brown on the bottom and cook through the bottom half (about 10 minutes).
Put a plate over the frying pan. It is important that the plate be slightly bigger than the frying pan. (Over the sink) flip the frying pan over so the tortilla is on the plate. Slide the tortilla back into the frying pan so the
browned side is facing up. Brown the other side for the same amount of time.
Serve with homemade ketchup or the sauce from the Patatas Bravas - so yummy!