Marinate chicken with all marinade ingredients. Let it sit for at least 30 minutes. Pan-fry until lightly charred and about 70% cooked. Set aside.
In the same pan, heat oil and sauté onions, ginger garlic paste, and green chillies until soft and fragrant. Add tomato purée and Tikka masala, cook for 8–10 minutes until the masala deepens in colour and thickens.
Blend the sauce until smooth (optional but gives restaurant-style texture).
Return sauce to pan, add butter/ghee, and stir in the chicken pieces. Coat well and simmer for a few minutes. Add a splash of water if needed.
Finish with heavy cream, mix gently, and let it simmer until silky and rich. Garnish with fresh cilantro.
