Preheat the oven to 190 degrees Celcius. Add the sweet potato chunks into a roasting dish with a splash of olive oil and the smoked paprika. roast until just softened (20-30 min). Remove and put to the side.
Heat the sunflower oil in a pot, at medium heat, and sautee the onions.
Add in the ginger and garlic and cook for another 2 min (until the garlic is cooked).
Mix in the 4 spices (coriander, turmeric, cumin and cayenne) and allow to cook for another 2 min.
Add in the chickpeas, tomato and vegetable stock. Bring it to the boil and then lower to a simmer for 10 min.
Add in the sweet potato, salt, sugar and spinach and allow to simmer for another 5 - 10 min (until the spinach has softened).
Ad in the coconut milk, garam masala and lemon juice and allow to slowly cook for another 10 min at low heat. I like to cook my Currys for slightly longer so that the flavour intensifies, or even make it in the morning and then simply reheat it for dinner.
Serve with your favourite rice and some Naan bread!