In a large bowl, mix yogurt, ginger-garlic paste, garam masala, turmeric, and Kashmiri red chili powder. Add the chicken pieces, making sure they're well-coated, and let it rest for 30 minutes to absorb the flavors.

Heat oil or ghee in a pan over medium heat. Sauté chopped onions and cashew nuts until the onions turn light brown. Transfer the mixture to a blender and blend until smooth.

In the same pan, add a little more oil if needed and increase the heat. Add the marinated chicken and roast for about 10 minutes until lightly browned. Set aside the chicken for later.

In the pan, heat additional oil or ghee, then add ginger-garlic paste and sauté for 1-2 minutes. Stir in the grated tomatoes, turmeric, and Kashmiri red chili powder. Cook until the oil separates from the mixture (approximately 7-8 minutes).

Add the prepared onion-cashew paste, milk, and a splash of water to create the gravy. Gently fold in the roasted chicken, cover, and simmer on low heat until the chicken is tender, stirring occasionally.

Optional: Garnish with a drizzle of cream for an extra touch of indulgence.