Peel the sweet potato, and cut it into dice. Toss it with some oil, and spread it out in a single layer on a baking tray. Roast at 190°C (Gas Mark 5 / 375°F) for around 25 minutes, until crispy around the edges.

While the sweet potato is roasting, heat a little more oil in a large frying pan. Add the vegetables, garlic and ginger, and cook for 5 minutes over a medium heat. Add the curry paste, and mix to combine.

When the sweet potato is ready, add it to the pan with the vegetables, along with the chopped tomatoes and a couple of handfuls of spinach. Simmer for a further 5-10 minutes, or until cooked to your liking (the sweet potato will break down more the longer you cook it).

If desired, stir in a little cream just before serving.

I like to serve the sweet potato curry topped with some cashew nuts - just toast them for a few minutes, in a dry pan over a medium heat, until lightly browned. Watch them carefully, as once they start to turn brown, they can burn quickly.