Peel the potatoes and slice into thin circles, a little less than a quarter inch thick. Place in a bowl of cold water until ready to use
Slice the onion in half and slice into very thin strips
Place a colander in a large pot of water and place a sheet of parchment paper on top. Add the potatoes and steam for 5-8 minutes or until the potatoes are translucent in the center.
Place the omelet pan on the stove, set to medium low heat, and add a quarter of a cup of olive oil.
Add the onions and sauté for 2-3 minutes or fragrant and translucent. Add the potatoes, one tsp of kosher salt and another few tablespoons of olive oil and continue to sauté, stirring constantly, for another few minutes.
In a large mixing bowl, whisk the eggs until well combined, then add the potato and onion mixture and stir to combine.
Add a few more tablespoons of oil to the pan, then add the potato, onion and egg mixture and use a spatula to lay the potato pieces down in an even layer.
Cook for several minutes on medium low heat until the edges of the eggs begin to cook, using a spatula around the rim of the pan to prevent sticking. When the eggs begin to firm up about a third of the way through the pan, remove the pan from the heat, place a large plate over the pan and flip in one quick motion.
Add the remaining oil and gently scoop the omelet mixture back in the pan (the cooked side should be facing up at this point). Cook for another 5-8 minutes or until the eggs firm but the center is slightly runny. You may want to check the center of the omelet by piercing it with a knife. Remove from the heat and gently scoop the tortilla onto a plate for serving. Cool for several minutes before slicing into wedges.