Mix together the marinade ingredients (greek yoghurt, turmeric, salt, black pepper, garam masala, lemon juice) and marinade the chicken in this yoghurt mix while you make the base
Heat pan, add oil and once hot add the chopped onions, let them turn light brown in colour
Add the garlic, chopped tomatoes, tomato puree, turmeric powder, coriander powder, cumin powder and Kashmiri chilli with a pinch of salt
Maintain medium heat and continue stirring and cooking for 5-10 minutes until the oil separates
Turn heat to low
Add the marinated chicken to the pan and mix gently, let this warm up slowly and bring to a gradual simmer
Cover and cook for 10-15 minutes or until the chicken is cooked through
Add the garam masala, kasuri methi and salt, mix well and taste
Cook uncovered for 5 minutes and add a finished touch of butter before serving
