Preheat the oven to 200°C. Peel the sweet potatoes, cut them into cubes of equal size. Finely chop the onion. Rinse the chickpeas and slice the tomatoes into small cubes.
Heat the olive oil in a frying pan. Add the onion, garlic, coriander, cumin and paprika powder. Add the finely sliced ginger and turmeric. Stir fry the ingredients for 2-3 minutes.
Add the sweet potato after 3 minutes. Fry for a further 5 minutes over a medium-high heat. Add the drained chickpeas to the pan. Pour in the coconut milk and bring to the boil.
Halve the Naga Jolokia lengthwise, remove the seeds and finely slice the flesh. Add the Naga Jolokia and the tomatoes to the pan. Allow to cook for 20 minutes, covered, over a low heat.
Squeeze the limes and season the curry with lime juice. Add the spinach in handfuls. Only add more spinach when the previous handful has wilted. Allow to cook for a further 3 minutes. Meanwhile, bake the naan bread in the oven.
Season the curry with salt and serve in bowls. Garnish the curry with the cashew nuts and fresh coriander or parsley.
