Mix the first 7 ingredients plus 1 1/3 tablespoons of the garam masala powder, add chicken, and marinate for 6 to 8 hours. Preheat a charcoal grill and cook the marinated chicken on skewers, turning periodically, until almost cooked through, about 10 to 15 minutes depending on the heat of your grill. Before serving, add the parcooked chicken, the remaining 2 teaspoons of garam masala powder, and salt to the masala sauce. Simmer for 7 to 10 minutes, stirring to prevent sticking. Just before removing from heat, stir in the cream and fenugreek. Present with the basmati rice pilau. Serves 4 to 5.