In a large bowl, combine the chicken pieces with yogurt, ginger-garlic paste, turmeric powder, red chili powder, garam masala, and salt. Mix well to coat the chicken evenly. Cover and marinate for at least 30 minutes, preferably in the refrigerator for 2 hours to enhance flavor.

Heat the vegetable oil in a large skillet over medium heat. Once hot, add the finely chopped onions. Sauté for about 5-7 minutes until they turn golden brown, stirring occasionally to prevent burning.

Add the marinated chicken to the skillet. Cook for about 10 minutes, stirring occasionally, until the chicken is browned on all sides.

Stir in the pureed tomatoes and cook for another 5 minutes until the mixture thickens and the oil starts to separate from the masala.

Add the coriander powder, cumin powder, and black pepper. Mix well and cook for an additional 2 minutes to allow the spices to bloom.

Pour in the coconut milk and water. Stir to combine, then bring the mixture to a gentle simmer. Cover the skillet with a lid and let it cook for 15-20 minutes, or until the chicken is cooked through and tender.

Taste and adjust seasoning if necessary. If the curry is too thick, add more water to reach your desired consistency.

Once done, remove from heat and garnish with fresh chopped cilantro before serving.