In a large bowl, combine the mutton pieces with the whisked yogurt, ginger-garlic paste, and a generous pinch of salt. Mix thoroughly to ensure the meat is well coated. Cover and let it marinate for a minimum of 2 hours to tenderize the meat and allow it to absorb the rich flavors.

In a heavy-bottomed pot or deep pan, heat the mustard oil over medium-high heat until it begins to smoke lightly, signaling that it's ready. Reduce the heat to medium and add the ghee. Toss in the cumin seeds, cloves, green cardamom pods, black cardamom pods, cinnamon stick, and bay leaves. Sauté the whole spices for a minute or two until they release a deep, inviting aroma.

Add the finely sliced onions to the pot and cook them until they turn a deep golden brown, stirring occasionally to prevent burning. This forms the flavorful foundation of the curry. Stir in the asafoetida and mix well to distribute its distinct fragrance.

Introduce the marinated mutton pieces to the pot, stirring vigorously to coat them evenly with the caramelized onions and spices. Cook over high heat for around 10 minutes, allowing the mutton to brown and develop a rich seared exterior.

Lower the heat and sprinkle in the Kashmiri chili powder, turmeric powder, fennel powder, and dry ginger powder. Stir the mixture continuously to toast the spices gently without burning, deepening the color and aroma of the dish.

Pour in enough water to just cover the meat. Bring the mixture to a boil, then immediately reduce the heat to low. Cover the pot with a lid and allow the curry to simmer slowly for 1½ to 2 hours, stirring occasionally to prevent sticking. This slow cooking process ensures the mutton becomes fall-off-the-bone tender and soaks up the intricate blend of spices.

Once the meat reaches desired tenderness and the sauce has thickened to your liking, taste and adjust the seasoning with additional salt if necessary. Garnish generously with fresh cilantro leaves and serve hot, preferably with steamed basmati rice or warm naan for a truly authentic experience.