With an electric whisk or by hand, mix the marinade ingredients to a smooth paste, smother over the chicken and refrigerate for at least four hours.
Remove the chicken pieces from the marinade, skewer and place under a hot grill until they are almost fully cooked through, and nicely charred.
Add all the tomatoes to a large pot on a low heat. When they have broken down (around 30 minutes), add all the masala ingredients except for the diced ginger, fresh chilli, butter and cream, along with half a cup of water (120ml).
Continue to cook over a low heat, stirring continuously, for another 20-25 minutes. It is ready when the oil separates and rises to the top – if it is too thick, add a little water.
Using hand blender, puree the sauce, strain and return to the pot.
Add the grilled chicken, diced ginger and chilli, and cook for another five to seven minutes, then stir in the butter and cream.
Check the seasoning and garnish with the ginger and coriander.
