In a large mixing bowl, combine yoghurt, ginger-garlic paste, Biryani masala, red Chilli powder, turmeric powder, cumin powder, coriander powder, garam masala, and salt. Mix well to form a smooth marinade.

Add the cubed mutton to the marinade, ensuring each piece is well coated. Cover the bowl with plastic wrap and let it marinate for at least 1 hour, allowing the flavours to infuse.

In a separate pot, bring water to a boil. Add soaked basmati rice and cook until it's 70% cooked. Drain the rice and set aside.

In a large, heavy-bottomed pan, heat cooking oil or ghee over medium heat. Add sliced onions and saute until golden brown and caramelized. Remove half of the fried onions for garnish.

Add the marinated mutton to the pan and cook until it is browned on all sides.

Layer the partially cooked rice over the mutton evenly. Sprinkle a bit of Biryani masala and fried onions on top.

Cover the pan tightly with a lid, and let the biryani cook on low heat for about 30-40 minutes or until the mutton is tender, and the rice is fully cooked.

Garnish the Mutton Biryani with fresh coriander leaves and the reserved fried onions.

Serve hot, accompanied by lemon wedges for a zesty touch.

Customize the spice levels according to your preference. Enjoy this flavourful Mutton Biryani with raita or a side of your choice!