🥔 The perfect tortilla de patatas

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As a proud Spaniard, one of my favorite dishes is the classic Spanish omelette. It’s fascinating how a dish with so few ingredients can have so many variations and spark endless debate: with or without onion, how runny it should be, whether to cut the potatoes into cubes or thin slices…

Throughout my life, I’ve tasted countless versions and, in recent years, have experimented with making it myself. Every version has its charm, but today I’m sharing the one I consider the best. My ideal tortilla includes onion, thinly sliced potatoes, and is cooked to a doneness level between 4 and 5.

This recipe serves about 2–3 people.

🥔 Ingredients

• 1 kg potatoes – any good frying variety such as Monalisa, Agria, or Kennebec
• 1 large white onion (or 2 medium ones) – sweet or Babosa types work well
• 6 large eggs
• Olive oil (recommended) or sunflower oil
• Salt

🔪 Mise en Place

Spanish omelette is a very simple dish (but not necessarily easy). Start by peeling the potatoes and slicing them thinly, about 3–5 mm thick. Place them in cold water and rinse thoroughly to remove excess starch, repeating this process three times.

Dice the onion into a medium-fine brunoise.

🍳 Cooking the Potatoes

The potatoes should be slowly confited: add a generous amount of oil to the pan, leaving a few slices just above the oil level.

I recommend extra virgin olive oil for its flavor, but sunflower oil also works.

• Cook the potatoes over medium heat until they’re soft.
• Raise the heat to medium-high briefly to add a touch of color and texture.
• Avoid constant stirring to prevent them from turning into purée (it’s fine if they break a little).
• Remove from the pan, drain well to remove excess oil, and season with salt.

🧅 Caramelizing the Onion

Some people cook the onion along with the potatoes, but I believe it tastes much better caramelized separately. I usually do this while the potatoes are cooking.

1. Add a drizzle of oil to the pan, the chopped onion, and a pinch of salt (helps release water).
2. Cook over medium-high heat, stirring often until translucent.
3. Lower the heat and continue cooking, adding a splash of water occasionally to prevent burning.
4. Cook until it reaches a deep brown color and sweet flavor—about 40 minutes, similar to the potatoes.

🥚 Mixing Potatoes, Onion, and Eggs

• Beat the 6 eggs with a fork, avoiding too much foam.
• Add the hot potatoes, caramelized onion, and a pinch of salt.
• If the potato slices are intact, break them into ~2 cm pieces with a fork.
• Mix well and let rest for 5 minutes to allow the mixture to bind.

Tip: Taste the raw mixture to adjust seasoning. If you prefer not to taste it raw, cook a small sample in the pan or microwave to check salt levels.

🔥 Choosing the Doneness

Debate about tortilla doneness is endless. The famous Betanzos tortilla is completely runny inside, while in other places it’s almost solid.

I prefer a set exterior with a juicy, slightly undercooked center. In the EU, undercooked eggs are generally safe if refrigerated and in good condition. If unsure, take precautions:

• Use fresh, refrigerated eggs with clean, uncracked shells
• Use pasteurized eggs for extra safety (I personally don’t)

🍽️ Cooking the Tortilla

This is the critical step: all the effort can be ruined if it sticks to the pan.

My process:

1. Preheat a 20 cm non-stick pan.
2. Add a thin layer of oil and reduce to medium heat. (Too much oil prevents sticking but leaves a greasy coating.)
3. Pour in the mixture.
4. Cook for 1½ minutes, shaking the pan constantly to shape the edges. Use a spatula to help form a clean border.
5. Remove from heat, cover with a plate, and flip carefully.
6. Reheat the pan, add a little more oil, and cook the other side for ~1 minute.
7. Flip again onto a plate—the tortilla is ready.

🧑‍🍳 Tricks to Prevent Sticking

• Use a good-quality non-stick pan dedicated to tortillas and eggs. Avoid high heat, acidic foods, metal tools, and harsh cleaning.
• Don’t reuse the same pan used for frying potatoes unless thoroughly cleaned and dried first.
• Special double pans exist, but I find a good non-stick pan sufficient.
• Preheat the pan properly before adding the mixture.
• Spread the oil evenly over the surface.

📚 Sources

My mother, my grandmother, and plenty of internet research.

💡 Extra Tips

One of the most common mistakes is under-seasoning. The best advice my mother gave me: season at every stage. Add a pinch of salt to the potatoes, the onion, and the eggs. And if you’re brave, taste the mixture before cooking.