Heat a large fry pan with a medium heat and add in the olive oil (I used a 12 inch / 30 cm nonstick pan)

In the meantime, cut the potatoes (peeled) into small 1/4 inch (.625 cm) thick bite-sized pieces, finely chop the onions

Add the chopped onions into the hot fry pan, mix continuously, after 3 to 4 minutes and the onions are lightly translucent, add in the chopped potatoes, mix together, then mix every 3 to 4 minutes so everything evenly fries

Meanwhile, crack the eggs into a large bowl, add in the chopped parsley and season with sea salt & black pepper, whisk together, slice the block of cheese into 1/4 inch (.625 cm) thick slices, about 7 to 8 slices will do

After 20 to 25 minutes and the potatoes are golden fried, season with sea salt & black pepper, mix together, then remove from the heat, transfer everything into the bowl with the whisked eggs, making sure to reserve any olive oil in the pan, mix together and set aside

Heat the same fry pan with a low-medium heat, add in more olive oil or remove some if needed, you want about 1 tbsp (15 ml) in the pan

After 3 to 4 minutes add in half of the potato and egg mixture, make sure to spread it around so it covers the entire surface, add the slices of cheese, all in a single layer, pour the rest of the egg and potato mixture, again making sure to cover the entire surface and in a flat layer

After 4 to 5 minutes it's time to flip the omelette, place a plate that is slightly smaller than the pan over the omelette, in one swift move flip the pan into the plate, then slide the omelette back into the pan, gently push down on the omelette and then compact it from the outer edges towards the center, this is what gives it that classic rounded edge

Once the eggs are fully cooked through, about 4 to 5 minutes per side, remove the pan from the heat, slide the omelette into a serving dish, serve warm, at room temperature or even chilled, enjoy!