Heat the oven to 230C/210C fan/gas 8. Chop the sweet potatoes into 2-3cm cubes.

Tip into a large, shallow roasting tin, drizzle with the oil and season with salt and pepper. If you're adding additional veg or herbs, such as sliced red onions, garlic cloves and thyme, tip these in as well. Toss everything together to coat in the oil, then roast for 20 mins. Toss again to ensure the potatoes cook evenly, and roast for another 15-20 mins until the potatoes are lightly browned on the outside and tender when pierced with a fork or knife.