1 10-inch (25cm) skillet, non-stick or well-seasoned cast iron
Ingredients
2lbs(900 grams or 5-6 medium) waxy potatoes (like Yukon Gold), about 5 cups of peeled, sliced potatoes
1large onion
8largeeggs
1¼teaspoonsfine sea salt
½teaspoonwhite pepper, optional
1½cups(360 ml) extra-virgin olive oil
Instructions
Peel and slice the potatoes thinly, just under ¼-inch thick (about ½ cm). Dab handfuls of the sliced potatoes dry with a paper towel or clean kitchen towel, removing as much moisture as you can.
Peel the onion, cut it into quarters, and slice them as thin as the potatoes.
Pour the olive oil into a 10-inch (25 cm) non-stick skillet. Heat the oil over medium-high heat until it shimmers.
While the oil is heating, beat the eggs in a large bowl (big enough to add the cooked potatoes later) with the salt and white pepper. The salt will make the eggs get a little 'glassy' and dark-coloured as they sit - that helps them stay more tender when cooking.
When the oil is hot, carefully add the sliced potatoes and onions, a handful at a time so they don't splash. Stir them gently to coat them with the oil.
Cook the potatoes in the oil for 15-18 minutes, until they are just fork tender. Adjust the temperature to keep the oil bubbling gently and steadily. Stir them occasionally, lifting the bottom slices to the top, so they cook but don't brown.
Set a metal colander or large sieve into a bowl, then carefully pour in the hot potatoes and oil to drain. Let them drain and cool for 5 minutes. Wipe the outside of the skillet clean, but do not wash it.
Pour the drained potatoes and onions into the beaten eggs, stirring gently to combine everything without breaking up too many of the potatoes.
Put the skillet back onto the stovetop on medium heat and add 2 tablespoons of the oil back into it. Pour the potato-egg mixture into the skillet and pat the potatoes down with a spoon so the top of the tortilla is even. Cook, uncovered, on medium heat for 6 to 8 minutes, until the edges are set and the bottom is golden-brown when you carefully lift up one edge a bit.
Invert a large, flat dinner plate or a lid onto the top of the skillet. Using an oven mitt, place one hand flat on top of the plate, then quickly and confidently flip the skillet and plate together so the plate is on the bottom and the tortilla has flipped onto the plate. (Do this over the sink or countertop to prevent drips onto the stovetop.)
Replace the skillet onto the stovetop. Add another tablespoon of the reserved oil, and carefully slide the tortilla off the plate and back into the skillet (cooked-side-up), using a spatula to help push along any potatoes that stick to the plate. Using the spatula, push the edges of the tortilla in and under, all the way around the outside of the skillet to help it form a neat puck shape.
Lower the heat a notch, and cook the second side of the tortilla for another 6 to 8 minutes, until the bottom is golden-brown when you lift the edge carefully, and the center feels almost firm to the touch. Leave it in the pan for 5 minutes to cool, then slide it onto a serving plate (or invert it so the nicest side is on the top).
Cut into 6 to 8 wedges. Serve the potato tortilla warm, at room temperature, or chilled.
Notes
Tortilla de Patatas is great for breakfasts, snacks, packed lunches or picnics, or for a light meal with a salad and some crusty bread.Use tabasco sauce instead of white pepper, if desired, or omit the pepper altogether.If you use a larger skillet, you will need a very large platter or lid, and it will be harder to flip, so I recommend a 9 or 10-inch skillet (use only 1½ lbs of potatoes for a 9-inch skillet).Replace some of the potatoes with other ingredients of your choice (cook them in the oil along with the potatoes and onions): chopped sweet red or green bell peppers, chopped broccoli or asparagus, peas, sliced mushrooms, olives, sliced or crumbled chorizo or other Spanish sausage, chopped ham, etc. Reuse the drained olive oil for making more tortillas - it can be used 3 or 4 times - or for cooking or frying other dishes. Strain the oil through a fine-meshed sieve into a jar, and keep it in the refrigerator. It will last for up to a month. Olive oil will solidify when it is chilled, but will re-liquify when heated (just scoop it out of the jar with a spoon to use it). Alternately, for a lighter version, you can use only ¼ cup (60ml) of olive oil and cook the potatoes with a lid, stirring often. Don't drain the oil. The potatoes will break up more, but the tortilla will still be very tasty.