Blend cashews, almonds, desiccated coconut, and water into a smooth paste.
In a large bowl, combine the nut paste with all the marinade ingredients.
Add chicken and coat well. Marinate for at least 2 hours, or overnight for best flavor.
Heat oil in a heavy pan. Add curry leaves and let them crackle.
Transfer the entire marinated chicken into the pan. Cook on low-medium heat, covered, for 40-45 minutes, stirring occasionally so the masala doesn't burn.
Once oil separates, the gravy deepens to a darker red, and the chicken becomes tender and almost fall-off-the-bone, add fresh cream and chopped coriander. Switch off heat.
Rest for 10 minutes before serving. Serve with soft roti or rice.
