# Spanish Tortilla (Tortilla Espanola)

Spanish tortilla is a thick, golden omelette of tender potatoes and sweet onions, set with eggs. It is a staple of tapas bars and good hot, warm or cold.

The potatoes poach slowly in olive oil, which makes them silky, and a quick flip finishes the tortilla with a creamy center.

- Total time: 55 min (prep 15 min, cook 40 min)
- Serves: 6
- Per serving (estimated): 310 kcal, 11 g protein
- Cuisine: Spanish. Category: Appetizer. Diet: vegetarian, gluten-free, dairy-free.

## Ingredients

- 600 g waxy potatoes (Yukon gold), peeled and thinly sliced
- 1 medium onion, thinly sliced
- 1/2 cup (120 ml) olive oil
- 6 eggs
- 1 tsp salt
- 1/4 tsp black pepper
- Parsley or aioli, for serving

## Method

1. Heat the olive oil in a 10 inch (25 cm) nonstick skillet over medium-low heat, about 275°F (135°C).
2. Add the potatoes and onion with 1/2 tsp salt. Cook gently for 20 to 25 minutes, turning often, until the potatoes are tender and just beginning to break apart but not browned.
3. Drain the potatoes and onion in a sieve over a bowl, saving 1 tbsp of the oil.
4. Beat the eggs with the remaining salt and pepper in a large bowl. Stir in the warm potatoes and onion and let them sit for 10 minutes so the eggs soak in.
5. Heat the reserved 1 tbsp oil in the same skillet over medium heat. Pour in the mixture and spread it flat.
6. Cook 5 to 6 minutes, shaking the pan gently, until the edges are set and the bottom is golden.
7. Place a large plate over the pan, flip the pan upside down so the tortilla lands on the plate, then slide it back into the pan.
8. Cook 3 to 4 minutes more, until golden and just set but still slightly creamy in the middle, reaching 160°F (71°C).
9. Rest 10 minutes, then slice into wedges and serve warm or at room temperature.

## Why it works

- Cooking potatoes slowly in plenty of oil softens them without browning, so they turn silky and sweet.
- Onion cooked low and slow becomes sweet and adds moisture and flavor.
- Draining the oil leaves a rich flavor without a greasy tortilla.
- Letting the potatoes soak in the eggs for 10 minutes means the egg seeps in and binds every slice.
- A short second cook keeps the center creamy and the egg tender.

## The science

- **Poaching in oil.** Cooking potatoes in warm oil at about 275°F (135°C) heats them evenly and softens their starch without much browning. The potato stays moist and silky instead of crisp. Waxy potatoes hold their shape better than starchy ones.
- **Gentle heat sets the egg.** Eggs set at 145 to 160°F and turn dry and rubbery when pushed higher. Cooking the tortilla on medium heat and pulling it while the center is slightly soft lets residual heat finish it, keeping the texture custardy.

## Tips

- Use a nonstick pan so the tortilla flips and releases cleanly.
- Slice the potatoes thin and even so they cook at the same speed.
- Flip over the sink or a tray in case any egg drips.

## Mistakes to avoid

- Browning the potatoes makes the tortilla dry and bitter, so cook them gently.
- Cooking the tortilla until fully firm makes it dry, so stop while the middle is still slightly soft.
- Skipping the rest makes the egg loose and runny, so let the potatoes sit in the eggs first.

## Variations and swaps

- Add chorizo or serrano ham for a meaty tortilla.
- Add roasted red pepper and spinach.
- Serve in a baguette as a bocadillo.
- Swap Yukon golds for red potatoes; they have a similar waxy texture.
- Swap the onion for a leek for a softer, milder flavor.
- Swap olive oil for half olive oil and half neutral oil to lighten the flavor.

## Storage

Refrigerate for up to 3 days, covered. Serve cold or at room temperature, or warm gently in a 325°F (165°C) oven until it reaches 165°F (74°C).

## FAQ

**What potatoes are best for Spanish tortilla?**

Waxy potatoes such as Yukon gold or red potatoes are best, since they hold their shape and turn creamy. Starchy russets break apart and make it crumbly.

**How do I flip a Spanish tortilla?**

Place a large plate over the pan, hold it firmly and flip the pan over so the tortilla drops onto the plate, then slide it back into the pan. Do it quickly, over the sink if you need to.

**Should the tortilla be runny in the middle?**

Traditional tortilla is creamy and slightly soft in the center, not liquid. For safety, aim for a center temperature of 160°F (71°C) and cook it a bit longer if you prefer it firmer.

**Can I make Spanish tortilla ahead?**

Yes, it is better after resting. Make it up to 3 days ahead and serve it cold or at room temperature.

**Do I need so much oil?**

The potatoes cook in a generous amount of oil, but you drain it afterwards and only 1 tbsp ends up in the final pan. You can reuse the leftover oil once.

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Source: https://cookingscientist.com/recipes/spanish-tortilla (Cooking Scientist). Learn the science of cooking in the Cooking Scientist app for iPhone and iPad: https://apps.apple.com/app/id6830326846