01 -
Heat olive oil in a nonstick medium-sized (30cm/12-inch) pan. Fry potatoes until crispy, golden and tender. Add onion and fry until transparent. Drain oil completely.
02 -
Return potatoes and onions to pan, arranging in a single layer. Reduce heat to low.
03 -
Beat eggs with salt and pepper. Pour over potatoes and onions, moving ingredients around with a plastic spatula to ensure eggs cook evenly on the bottom.
04 -
When bottom is set but top is still slightly runny, place a large plate over pan. Hold plate firmly and flip tortilla onto plate. Carefully slide tortilla back into pan to cook other side.
05 -
Continue cooking, gently shaking pan occasionally, until completely cooked through.
06 -
Place a clean plate on top of tortilla and flip again to remove from pan. Garnish with parsley if desired. Serve hot or cold, cut into squares.