1. Heat 2 tbsp of oil in a large lidded ovenproof casserole pan. Season the chicken thighs and fry in two batches until browned. Remove the chicken from the pan and set aside.
2. Add the remaining oil to the pan. Add the onion and fry gently for 10 minutes until it begins to soften. Meanwhile, bash the cardamom pods with the end of a rolling pin to split the husks and remove the seeds. Add the seeds, Shemin’s Indian Curry Paste and water to the pan, and cook gently for 4-5 minutes.
3. Add the chopped tomatoes, stock, lentils, sugar and vinegar to the pan, then add the chicken. Bring to the boil. Cover and place the pan in the oven for 50 minutes on 200°C / Gas mark 6 or until tender.
4. Stir in the yoghurt, check the seasoning and serve topped with coriander and some basmati rice.