Clean 500 grams of mutton pieces and keep aside.
In a pan, dry roast 2 tablespoons of coriander seeds, 1 tablespoon of cumin seeds, 1 teaspoon of fennel seeds, 5 cloves, 2 inch cinnamon stick, 4 green cardamoms, and 10 black peppercorns until aromatic. Cool and grind to a fine powder.
Soak 20 cashew nuts in warm water for 15 minutes and grind to a smooth paste.
Heat 4 tablespoons of ghee in a pressure cooker. Add 2 finely sliced onions and sauté until golden brown.
Add 1 tablespoon of ginger-garlic paste and sauté for 2 minutes.
Add the mutton pieces and cook on high heat for 5 minutes.
Add the ground spice powder, 1/2 teaspoon of turmeric powder, salt to taste, and mix well.
Add 1 cup of water, close the lid of the pressure cooker, and cook for 4-5 whistles or until the mutton is tender.
Release the pressure and open the lid. Add the cashew paste, 1 cup of coconut milk, and simmer for 10 minutes.
Garnish with chopped coriander leaves and serve hot with rice or naan.