• 300 g (10 ½ oz) kumara, peeled and cut into 1 cm (½ in) cubes
• 200 g (6 1½ oz) potatoes, peeled and cut into 1 cm (½ in) cubes
• 2 teaspoons spicy smoked paprika
• 200 ml (7 fl oz) extra virgin olive oil
• 1 large red onion, peeled and finely sliced
• 3 tablespoons sherry vinegar or balsamic vinegar
• 10 large eggs, lightly beaten
• 125 g feta, roughly crumbled
• 3 spring onions, finely sliced
• 1 ½ teaspoons sea salt
• freshly ground pepper

Preheat oven to 200°C/400°F/Gas Mark 5. Mix kumara and potatoes with paprika and half the oil. Lay on a roasting tray and bake until potatoes are just cooked. Meanwhile, fry onion in 2 tablespoons of the oil until caramelised. Add vinegar and cook until it evaporates. Crack eggs into a bowl and lightly whisk, then add onion and kumara mixtures, along with the oil they were cooked in. Add feta, spring onions, salt and pepper and mix well.

Heat a 24 cm (9 ½ in) ovenproof frying pan, add remaining oil and when it begins to smoke (just a few seconds) add the egg mixture all at once. Leave to bubble for 10 seconds, then shake (or toss if you’re feeling confident), bringing the cooked outer reaches into the centre and the runny centre to the outside. Do this a few times then turn heat down and cook 1 minute.

Transfer to the top shelf of the oven and cook 8-10 minutes. It’s ready when the eggs are just set. Cool 5 minutes then give the pan a gentle shake to loosen the tortilla, using a blunt knife to help if needed. Invert onto a plate. Cool before covering and storing in the fridge.