Marinate chicken in tandoori paste for 2 hours or overnight.(Cover the meat or follow instruction on the jar).
Put cloves, cardamom seeds, black peppercorns in the mortar and pestle then crush. Add cinnamon white pepper and brown sugar.
Cook onion with ginger and garlic in butter until well browned, Add the spice mix and a pinch of salt. Add tomatoes and tomato paste; I use a stick blender to mix the sauce, let simmer and reduce for 15-20.
Simmer the chicken in the sauce until cooked then stir in cream. Serve with rice and pappadums.