This is a lovely supper dish, perfect warm from the oven and served with a green salad, although I think it tastes even better the next day, for a satisfying and delicious lunch. The saltiness of the feta works beautifully with the sweet potato, with the chilli giving the whole dish a nice kick. This is a doddle to wrap up and take into work and it can be reheated in a microwave.

Preparation time: 45 minutes

Cooking time: 20 minutes

600g sweet potatoes

3 red onions, peeled

2 cloves garlic

2 dried red chillies

Olive oil

10 free-range eggs

50ml milk

Salt and pepper

A small handful of mint leaves, roughly chopped

150g feta cheese

Pre-heat the oven to 200C/ 400F/gas 6. You will need a large paella dish or a shallow circular ovenproof dish about 28cm in diameter. Scrub the sweet potatoes and then cut them up into 2.5cm chunks, skin and all. Peel the red onions and cut them into one-eighths. Mash the garlic cloves in a pestle and mortar with a teaspoon of sea salt, the dried chillies and, when they are smashed into a purée, drizzle in two tablespoons of olive oil. Toss the sweet potatoes and onion wedges in the chilli oil and roast in the oven for 30-40 minutes until cooked through and turning golden. Turn the oven down to 180C.

Meanwhile, break the eggs into a large mixing bowl and whisk with salt, pepper and the milk. Stir in the mint, feta, and the onions and sweet potatoes when they are cooked, together with another tablespoon of olive oil. Heat the paella dish on the stove until very hot. Add two tablespoons of olive oil, wait for it to heat up, then pour in the egg mixture. Cook for 5 minutes before transferring to the oven, then cook for 15-20 minutes until the eggs look just set and the frittata is more or less firm to the touch. Serve at room temperature or slightly chilled with a green salad.

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