Sweet potato, aubergine and chickpea curry

1) Heat the olive oil in a large pan and cook the onion, chickpeas, sweet potato, garlic, chilli and spices for five minutes over a medium heat, stirring constanly to prevent sticking.
2) Add the remaining olive oil and the aubergine.
3) Cook for 5 minutes, stirring often, until the aubergine is coloured.
4) Add the stock and a pinch of salt, then cover the pan, lower the heat and simmer for 15 minutes or until the aubergine and sweet potato are cooked.
5) Sprinkle with fresh coriander and thyme and serve.