Remove skin, wash and cut chicken into eight pieces on the bone. Grind ginger and garlic to a fine paste. Blanch tomatoes in boiling water for two to three minutes. 

Drain. Peel the tomatoes and puree them in a blender.Marinate the chicken pieces in ginger-garlic paste, garam masala powder, red chilli powder and salt for an hour. 

Heat butter in a kadai. Add the marinated chicken. Add green chillies and continue to stair for a minute. Add tomato puree and half a cup of water and cover and cook on medium heat for fifteen minutes or till almost done. 

Stir in the fresh cream and mix gently. Remove from heat. Place coal on open flame and heat till it becomes red hot then Steam on Karahi.