Traditional Spanish tortilla

Method

1. Begin by making the ancho oil. Add the oil and garlic to a saucepan over a low heat and cook gently until the garlic is soft (around 20 minutes). Add the chopped ancho chilli and cook for a few more minutes until the oil turns reddish. Set aside until needed.
2. For the mojo verde, add all the ingredients except the coriander leaves to a blender with a pinch of salt and black pepper. Whizz for around 1 minute until smooth, then add the coriander leaves and whizz again briefly (don’t run the motor for too long otherwise you’ll lose the vibrant green colour). Taste and check the seasoning; it may need more salt or vinegar. Cover and reserve in the fridge until needed.
3. Put the skate fillets in a small saucepan with the garlic and chilli, pour over the olive oil to cover and set over a low-medium heat. After the oil has warmed up, gently cook/confit the fillets for just a few minutes until opaque and cooked through. Lift them out of the oil and set aside.
4. For the tortilla itself, fill a deep-fat fryer or deep pan two-thirds full with oil and heat to 180°C. Meanwhile, use a mandoline to cut the quartered potatoes into 2mm slices (you can use a knife, but it will take longer as it’s important to ensure even thickness throughout so they all cook at the same speed).
5. In a large mixing bowl, mix the sliced potatoes and onions together, breaking up the onions into individual slices. When the oil is up to temperature, carefully add the veg mixture to the oil and deep-fry for 2-3 minutes until the potatoes are soft, cooked through and have a very light golden crust forming. They shouldn’t be crisp or deeply coloured.
6. Lift the potatoes and onions out of the oil with a slotted spoon, draining off the oil.
7. Transfer to a mixing bowl with a pinch of salt and pepper. While the potato mixture is still hot, crack in 6 eggs and beat very well with a fork (don’t worry if some of the potatoes break up).
8. You’ll know the tortilla is properly mixed when the eggs turn foamy and produce little bubbles. If the mixture feels very stiff, you can beat in a seventh egg – it should be a little runny rather than thick. Season with salt and a little white pepper.
9. If using, gently stir in the confit skate, 2 tbsp of the mojo verde and a drizzle of the ancho chilli oil. Divide the mixture in half and put in 2 bowls.
10. Put a small deep frying pan (around 20cm) over a medium-high heat with enough olive oil to coat the base. Once shimmering hot, add a bowl of the tortilla mixture and leave to cook, undisturbed, for 1 minute.
11. Hold a plate over the pan and confidently flip the tortilla onto it, then slide it back into the pan and cook for another minute on the other side. This will give you a tortilla with a runny centre; you may want to cook it for an extra minute or so if you prefer it firmer.
12. Slide the tortilla onto a plate and garnish with more ancho oil (if using), plus a few herbs or mixed salad leaves. Repeat with the remaining tortilla mixture.