Heat a large fry pan with a medium heat and add in the olive oil

While the oil is heating, roughly chop the large onion, then add into the hot pan, mix every 1 to 2 minutes so the onion evenly sautees

In the meantime, cut the potatoes (peeled) into small ¼ inch (.635 cm) pieces

After 5 to 6 minutes and the onion is translucent, add in the potatoes, mix every 3 to 4 minutes that way everything evenly cooks

While the potatoes are cooking, crack 6 eggs into a large bowl, season with sea salt & black pepper and whisk together, crack another 2 eggs into a separate bowl, season with salt & pepper and whisk together

To make the tuna salad, drain the cans of tuna into a fine sieve with a bowl underneath, flake the tuna, then add into a bowl, along with the mayonnaise, the small onion finely chopped, the clove of garlic finely grated, the parsley and season with sea salt & black pepper, mix together until well mixed

After frying the potatoes for 20 to 25 minutes and they´re golden fried, remove from the heat, transfer into the bowl with the 6 whisked eggs, trying to reserve the oil in the pan, then gently mix together

Using the same pan, heat it with a medium to low medium heat, if there is no oil left, add in about 1 tbsp spoon (15 ml)

After a couple of minutes add in the potato and egg mixture, make sure it´s all in a flat layer, after 3 to 4 minutes, run a spatula through the outer edges, to ensure the omelette is not sticking to the pan, then place a plate that is slightly smaller than the pan over the omelette and in one swift move flip the pan into the plate, slide the omelette back into the pan, using the back of the spatula, compact the omelette towards the center, to give it that rounded edge, cook for another 3 to 4 minutes or until the eggs are cooked through, then remove from the heat

Using the same pan with the same heat, add in the 2 whisked eggs (add more olive oil if needed), cook in the same method, but for 1 to 2 minutes per side

To assemble the omelette, add the tuna salad over the potato omelette, making sure to evenly spread it around, then top off with the regular omelette, serve warm, at room temperature or even chilled, enjoy!