Peel and cut the potatoes (I made mine with the help of a mandolin) and put them in a medium skillet with the olive oil over low heat.
While the potatoes are cooking and browning, beat the eggs and milk, season with salt and pepper and set aside.
When you pinch the potatoes with a knife and they are soft, they are done, add the onion, let it cook for a couple of minutes. Then add the egg mixture.
It can take anywhere from 10 to 25 depending on the pan and flame. When you see that the first side is 85% cooked, turn it over and cook the rest.
You can serve it immediately as a meal with some salad or let it cool and cut it into bite-sized pieces.