Jordan Bourke's Pak choi, sweet potato and chorizo frittata

1. Preheat the oven to 200˚C, gas mark 6. Put the sweet potatoes in a large roasting tin and toss with 1½ tbsp oil; season. Roast for 15 minutes until golden and almost tender. Toss the pak choi, onion, tomatoes and chorizo in ½ tbsp oil, season and add to the roasting tin. Roast for 10 minutes.

2. Crack the eggs into a large bowl, whisk and season. Put a medium-large ovenproof frying pan (24-26cm) over a medium heat, then add ½ the sweet potato mixture. Pour over the beaten eggs and scatter over the remaining sweet potato mixture. Cook for about 5 minutes until starting to set at the edges, then transfer to the oven and bake for about 15 minutes, until the frittata has risen and set. If it is still uncooked in the centre, cover with foil and cook for another few minutes until just firm.

3. Meanwhile, put the parsley, garlic and remaining 4 tbsp oil in a bowl and whisk together; season. Let the frittata cool a little, then drizzle over the parsley oil and serve at once.