Prepare the Marinade: Blend ginger, garlic, chilies, cumin, coriander, chili powder, garam masala, lime juice, salt, and yogurt into a smooth paste.
Marinate the Chicken: Coat the chicken pieces well in the marinade. Cover and refrigerate at least 6 hours or overnight.
Grill the Chicken: Preheat grill to medium-high. Place marinated chicken on a grill rack or pan. Brush with melted butter. Grill 8–10 minutes, turning halfway, until cooked and slightly charred.
Make the Sauce: In a large pan, warm passata and tomato paste over medium-low heat. Stir in cream and sugar. Add grilled chicken pieces. Simmer gently 10 minutes until heated through and sauce is smooth.
Serve: Transfer to a dish. Garnish with ginger, coriander, and pomegranate seeds. Serve hot with naan or rice.