Sweet potato, okra and chickpea curry

Method

1. Heat the olive oil in a large frying pan. Add the onions, fry for 3-4 minutes, then add the sweet potatoes and fry for 15 minutes until the potatoes are almost cooked. Stir regularly to prevent sticking.
2. Stir in the curry paste, then add the okra and fry for a minute. 
Add the tomatoes, fill one of the tins three-quarters full with 
cold water, add to the pan, then simmer over a low heat for 
15 minutes.
3. Stir in the kale, chickpeas 
and yogurt, then bring back to 
a simmer. Cook for 2-3 minutes until the kale has wilted and the sweet potato is tender.
4. Taste and season with the 
lemon juice and some salt and pepper. Scatter with coriander leaves and serve with yogurt, rice and lemon wedges, if you like.