Heat a nonstick fry pan with a medium heat and add in a generous ½ cup extra virgin olive oil
Roughly dice 1 large onion and add to the pan with the olive oil, mix so all the onions are coated in the olive oil and let the onions poach in the olive oil
Meanwhile, peel & wash 3 medium sized potatoes, then cut each one into 4 evenly sized quarters, cut each quarter down the middle and then cut into ¼ inch (.625 cm) thick pieces
After cooking the onions for 5 to 6 minutes and they are translucent, add in the chopped potatoes, mix together so all the potatoes are coated in the olive oil, mix every 2 to 3 minutes so everything is evenly cooked
While the potatoes are cooking, crack 6 large eggs into a large bowl, whisk together until well combined
After cooking the potatoes for 22 to 24 minutes and they have a golden fried color, they should be perfectly cooked, just pierce them with a toothpick to ensure they are all fully cooked, remove the pan from the heat and transfer the potatoes & onions into the bowl with the eggs, making sure to leave some of the olive oil in the pan, season generously with sea salt and mix together until well combined, set aside for 5 minutes
Heat the same pan with a low-medium heat and add in the egg & potato mixture, make sure it´s all in a flat single layer, after 2 minutes run a spatula through the outer edges, to ensure the eggs are not sticking to the pan
After 4 to 5 minutes it´s time to flip the tortilla to cook the other side, place the other pan over the bottom pan and hook together, firmly hold the handles and in one swift move flip the pans, remove the top pan, using the back of a spatula compact the tortilla from the outer edges into the center to achieve the rounded edge
After another 4 to 5 minutes, the tortilla should be perfectly cooked, remove the pan from the heat and transfer into a serving dish, enjoy!