In a pot, combine the mutton chops, onions, ginger garlic paste, salt, turmeric powder, and water. Mix well and bring to a boil.
Reduce heat to low, cover, and cook for 25-30 minutes or until the mutton chops are tender. Then, increase the heat to high and cook until the water has dried up.
Allow the mutton chops to rest for 6-8 minutes.
In a separate bowl, combine coriander powder, red chili powder, garam masala powder, mace powder, nutmeg powder, cumin seeds, green chili paste, lemon juice, yogurt, and tandoori masala. Mix well.
Add the cooked mutton chops to the spice mixture and coat them thoroughly. Cover and marinate for 30 minutes.
In a frying pan, heat cooking oil over medium heat. Add the marinated mutton chops and remaining marinade. Cover and cook for 5 minutes on each side or until golden brown.
Add charcoal smoke for 2 minutes.
Dish out, garnish with fresh coriander, and serve hot.