Tortilla espagnole

03 — Method

1. Peel the 1 kg (2.2 lb) of potatoes and slice them very thin, 2 mm (1/16 in), on a mandoline or with a sharp knife.
2. Slice the 2 yellow onions very thinly. The amount of onion varies across Spain, but this ratio is a classic.
3. Heat the 150 ml (⅔ cup) of extra-virgin olive oil in the large nonstick skillet over medium heat. Add the potatoes and onions and cook gently for 20 minutes, stirring often, without browning.
4. The potatoes should be soft and tender, not browned — poached in oil, not fried. Salt generously halfway through.
5. Drain the potatoes and onions in the colander over a large bowl, saving the flavorful oil for cooking the tortilla.
6. Lightly beat the 8 eggs in the other bowl with salt and pepper. Gently mix in the potatoes and onions and let stand for 10 minutes.
7. Heat 3 tbsp of the reserved oil in the skillet over medium-high heat. Pour in the egg mixture and cook over low heat for 6 minutes, loosening the edges with a spatula so it doesn’t stick.
8. Flip the tortilla by sliding it onto the plate and then back into the pan upside down. Cook 4 more minutes until golden outside but still slightly runny inside. Sprinkle with parsley.