Marinate chicken pieces with 2 tbsp curd, salt, ½ tsp ginger garlic paste, and ⅛ tsp white pepper powder. Let it rest for 1 hour.
Toast poppy seeds until lightly golden. Grind toasted poppy seeds and cashew nuts into a smooth paste with a little water.
Heat ghee and cooking oil in a heavy-bottomed pan. Add bay leaves, cinnamon stick, cloves, green cardamoms, and mace. Fry until aromatic.
Add onion paste to the pan and sauté until it turns light brown in color.
Mix in the remaining ginger garlic paste, coriander powder, and remaining white pepper powder. Cook for 1-2 minutes.
Add the marinated chicken along with all the marinade. Cook on medium heat for 8-10 minutes, stirring occasionally.
Add the poppy seed-cashew paste and mix well. Cook for 3-4 minutes.
Pour in the remaining yogurt gradually while stirring continuously to prevent curdling.
Add green chilies, milk, and water. Bring to a gentle simmer.
Cover and cook on low heat for 15-20 minutes until chicken is tender and sauce reaches desired consistency.
Finish with kewra water if using. Adjust salt and serve hot with steamed rice.