Purée chilli powder, cumin, garam masala, coriander, three garlic cloves, turmeric, cinnamon, ginger, and cashews in a food processor.
Add half the lemon juice and blitz until smooth, then stir in the yoghurt.
Coat chicken breasts in the marinade and chill for one hour.
Preheat the grill to its highest setting.
Grill the marinated chicken on foil for 12 to 15 minutes until browned and cooked.
Heat oil in a frying pan and stir-fry the cinnamon stick and cardamom pods for one minute.
Add the remaining garlic, chillies, and tomatoes and simmer for four to five minutes.
Add grilled chicken to the sauce and cook for five more minutes.
Whisk in chilled butter followed by cream and simmer for two minutes.
Season with salt and pepper and keep warm.
Combine flour and 250ml cold water and knead into a soft dough.
Divide dough into four balls and roll each into a disc 2mm to 3mm thick.
Cook chapatis in a very hot non-stick pan for 20 seconds per side until charred.
Brush cooked chapatis with melted butter and serve with the chicken.