Peel off the potatoes, cut them into small pieces, add some salt and fry them on the sunflower oil. Some prefer to boil the potatoes before placing them on the pan. I usually just fry them. Be careful not to make them too crispy. By doing so you will be sure that the soft potatoes will mix with the rest of ingredients better.
Cut the onions into small cubes and fry them as well, just try to make them really soft. Now break the eggs and beat them gently in the bowl. In the meantime add some salt. Then add fried potatoes and onions to eggs and mix it all together slowly. You can experiment with the amount of eggs you use, but generally eggs should create the basis of the dish that joins all the ingredients together. Now pour everything onto a hot frying pan, wait for 2-3 minutes and flip the sides (you can cover the frying pan with a big plate and flip the tortilla upside down by using the plate). Use something sharp to check if it’s done well inside. I prefer to leave it medium done, with the egg still a little bit liquid.
Serve it either cold or warm. You can cut it into small rectangles or bigger, pizza-like triangle pieces.