Clean and cut 500 grams of mutton into medium-sized pieces. Marinate the mutton with 1/2 teaspoon turmeric powder, 1 teaspoon red chili powder, 1 teaspoon ginger-garlic paste, and salt as per taste. Set aside for 30 minutes.
In a pan, dry roast 4-5 dry red chilies, 1 tablespoon coriander seeds, 1 teaspoon cumin seeds, 1/2 teaspoon black peppercorns, 1/4 teaspoon fenugreek seeds, and 1/4 teaspoon fennel seeds until fragrant. Cool and grind into a fine powder.
Heat 3 tablespoons of ghee in a heavy-bottomed pan or kadai. Add 1 finely chopped onion and sauté until golden brown.
Add the marinated mutton pieces and cook on medium heat for 10-12 minutes, stirring occasionally.
Add the ground masala powder, 1/2 cup of water, and mix well. Cover and cook on low heat for 30-40 minutes, or until the mutton is tender and the gravy thickens.
In a separate pan, heat 2 tablespoons of ghee and add 10-12 curry leaves. Fry for a minute and pour this tempering over the cooked mutton.
Garnish with chopped coriander leaves and serve hot with rice or roti.