Peel the potatoes, cut them into small pieces (or slices) and put them in a bowl with some cold water for 10 minutes.

Drain the potatoes and dry with kitchen paper.

In a heavy bottom non-stick pan, reheat the olive oil reserving 2 tablespoons, then add the potatoes and let them fry for about 10 minutes, turning occasionally (trying not to break them) and adjusting the heat so they sizzle but don’t crisp or brown.

When the potatoes are tender, transfer them with a skimmer to a sieve or lined plate and let them cool down.

Using a whisk, mix well eggs, milk, salt and pepper.

Add in the cooled potatoes, onions and mix.

Drain the oil from the skillet and wipe out the pan with a paper towel.

Heat the skillet on medium-high. Add the reserved oil. Let the pan and oil get very hot (to prevent the eggs from sticking), and then pour in the potato and egg mixture, spreading it evenly.

Cook for 1 minute and then lower the heat to medium-low for 8 to 10 minutes, cooking until the eggs are completely set at the edges, halfway set in the center, and the tortilla easily slips around in the pan when you give it a shake. You may need to nudge the tortilla loose with a knife or spatula.

Set the pan lid upside down over the pan. Lift the skillet off the burner and, with one hand against the lid and the other holding the skillet’s handle, invert the skillet so the tortilla lands on the lid (it should fall right out).

Set the pan back on the heat and slide the tortilla into it. Once the tortilla is back into the pan, cook until a skewer inserted into the center comes out clean, hot, and with no uncooked egg on it (another 5 to 6 minutes).

Transfer the tortilla to a serving platter and let cool at least 10 minutes. Cut into wedges or small squares, sticking a toothpick in each triangle, maybe add some basil leaves.