1 green chilli, finely chopped
8–10 curry leaves
large handful fresh coriander (leaves and stalks), finely chopped
2 tsp finely grated garlic
1 tsp finely grated ginger
1 large onion, diced
100g/3½oz baby spinach leaves, roughly chopped
2 large sweet potatoes, peeled and cut into 1.5cm/5/8in cubes
400ml/14fl oz chicken stock
400g tin chopped tomatoes
salt and freshly ground black pepper
1 cinnamon stick
2 tsp cumin seeds
1½ tbsp medium curry powder
1 tsp vegetable oil
100g/3½oz fat-free natural yoghurt, whisked (optional)
600g/1lb 5oz boneless, skinless chicken thigh fillets, cut into large bite-size pieces