Sweet potato Spanish tortilla

The Spanish tortilla is a humble recipe with a long history. It dates back to northern Spain in the 1800s, where it was referenced in a letter as a simple, nourishing meal made from potatoes and eggs.

In this version, I've swapped white potatoes for sweet potatoes, to add colour, vitamin A and more polyphenols. Polyphenols are naturally occurring plant compounds that aren't digested by us but instead are broken down by our gut bacteria into beneficial compounds. There's also a generous amount of olive oil, another rich source of polyphenols and a cornerstone of the Mediterranean diet.

It makes a brilliant brunch, and any leftovers are perfect for lunchboxes, making this a cook-once, eat-twice recipe. Serve with a simple tomato salad dressed with a punchy vinaigrette. 

Serves 4

Ingredients

2 large onions, peeled and thinly sliced 
2 medium sweet potatoes, peeled and thinly sliced 
5 tbsp extra virgin olive oil 
1 tsp smoked paprika 
8 eggs 
Salt and black pepper 

To serve 
4 ripe tomatoes, cut into wedges 
2 tbsp vinegar (red wine or sherry vinegar works well) 
1 tbsp extra virgin olive oil 
Pinch of mustard powder or ¼ tsp Dijon mustard 
Pinch of salt and black pepper

Method

Peel the potatoes and onions and slice into thin pieces - this is important to make sure they cook through in the time given.  

Heat 2 tablespoons of the olive oil in a large frying pan over a medium heat. Add the onions with a pinch of salt and cook for 8–10 minutes, stirring occasionally, until very soft and starting to be caramelised. 

Add another 2 tablespoons of olive oil, followed by the sweet potatoes and another pinch of salt. Stir well to coat everything in the oil, then cover with a lid and cook for around 6–8 minutes, or until the sweet potato is tender when pierced with a fork. Remove from the heat. 

Whisk the eggs with the smoked paprika, a generous pinch of salt and plenty of black pepper. Gently fold through the cooked onions and sweet potato. 

Lightly brush oil over a good-quality non-stick frying pan. Put over a low heat. When warm, pour in the egg mixture and cook over a low heat for 8–10 minutes until the bottom and edges are set and the centre is a bit wobbly but almost there. As it cooks, gently run a spatula around the edge to stop it sticking. 

If the top is still very runny after 8–10 minutes, place the pan under a hot grill for 1–2 minutes to help it set before flipping. 

Place a large plate or pan lid over the frying pan and carefully invert the tortilla onto it. Slide the tortilla back into the pan, top side down, and cook for a further couple of minutes just to set the eggs on that side. 

Transfer to a serving plate and leave to rest for a few minutes before slicing. 

To make the vinaigrette, whisk together the vinegar, olive oil and mustard with a pinch of salt and pepper. 

Serve the tortilla with the tomato wedges drizzled with the vinaigrette.