Spanish Tortilla

Ingredients

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• 600 g (1.3 lb) waxy potatoes peeled, sliced 1/8 inch (3 mm) thick
• 1 yellow onion about 7 oz (200 g), cut into thin strips
• 150 ml (5.1 fl oz) olive oil for slowly cooking the potatoes
• 6 eggs large
• salt about 1 teaspoon for the potatoes, 1/2 teaspoon for the eggs

Method

1. Peel the potatoes, halve them and cut into slices 1/8 inch (3 mm) thick. Halve the onion and cut it into thin strips. Toss both in a bowl with 1 teaspoon of salt.
2. Heat the olive oil in a nonstick skillet (9 to 10 inches / 24 to 26 cm) over medium heat until a potato slice sizzles gently in it. Add the potatoes and onion, lower the heat to low-medium and cook for 20 to 25 minutes, turning now and then, until the slices are soft and a fork glides in without resistance; they should be stewed, not brown and crisp.
3. Whisk the eggs in a large bowl with 1/2 teaspoon of salt. Drain the potato mixture in a strainer set over a bowl, saving the oil. Fold the still-warm potatoes into the eggs and let the mixture stand for 10 minutes so the flavors can come together.
4. Heat 1 tablespoon of the saved oil in the same skillet over medium heat and add the egg and potato mixture. Smooth the top and cook for 4 to 5 minutes, until the edge is set and the tortilla loosens when you shake the pan.
5. Set a flat plate larger than the skillet on top. Using oven mitts, flip the pan in one motion, slide the tortilla back into the skillet and tuck in the edges with a spatula. Cook for another 3 to 4 minutes.
6. Slide the tortilla onto a plate and let it rest for 5 minutes. Serve lukewarm or at room temperature, cut into wedges.

Tip: Strain the saved oil, let it cool and keep it in the refrigerator for up to 2 days, for example for frying potatoes.

Tip: The center may stay slightly moist. For pregnant women, small children and older people, cook the tortilla 3 to 4 minutes longer after flipping, until the center is firm and a knife comes out clean.