
In a bowl, combine yogurt, lemon juice, ginger-garlic paste, turmeric, red chili powder, coriander powder, cumin powder, and salt. Marinate the chicken pieces in this mixture for at least 30 minutes or up to 4 hours in the refrigerator.
Preheat oven to 400°F (200°C). Arrange the marinated chicken on a baking sheet and bake for 20-25 minutes, or until cooked through. Alternatively, grill the chicken until slightly charred.
While the chicken is baking, prepare the masala sauce. In a large pan or pot, heat butter or ghee over medium heat. Add chopped onions and sauté until golden brown.
Add ginger-garlic paste and green chilies (if using) to the pan and sauté for another minute until fragrant.
Pour in the tomato puree and diced tomatoes. Stir in the garam masala, red chili powder, coriander powder, cumin powder, and salt. Bring the sauce to a simmer and cook for 15-20 minutes, stirring occasionally, until the sauce thickens slightly.
Stir in the heavy cream or coconut milk (for a dairy-free option). Mix well to combine. Add the baked or grilled chicken pieces to the masala sauce. Simmer for another 5-10 minutes, allowing the chicken to absorb the flavors of the sauce.
Garnish with fresh cilantro leaves. Serve hot with basmati rice or naan bread. Enjoy!