In a bowl, mix all ingredients under the marinade section. Then, add the mutton pieces and mix well. Marinate for at least 1 hour or overnight for up to 10 hours for best results.
Heat oil and ghee in a large heavy-bottom pan or Dutch oven over medium-high heat. Add the onions and shallow fry for 10-11 minutes till they are golden brown.
Add the whole spices – cinnamon, cloves, cardamom, and cumin seeds. Saute for 30 seconds so their aroma releases.
Add the marinated mutton to the pan and mix everything well. Cook the mutton for 5-6 minutes, stirring frequently.
Add water and stir it with the mutton. Reduce heat to low, cover with lid, and cook for 60-80 minutes, stirring occasionally, until the mutton is tender.
Soak saffron strands in warm milk. Set this aside for 10 minutes.
Remove the cooked mutton from the heat. Spread half of the fried onions on top of the mutton. Spread half of the chopped mint leaves, and cilantro leaves over the mutton.
Now, layer the parboiled rice evenly on top. Using a spatula, flat the surface. Now, drizzle the melted ghee and saffron milk all over the rice. Spread the remaining fried onions, mint leaves, and cilantro leaves on top.
Cover with a tight lid and cook on the lowest flame for 20 minutes. You can also wrap a kitchen towel on the lid to get that tight-fitting lid to keep the steam inside while cooking the biryani.
Remove from heat and let the biryani rest for 5-10 minutes. Garnish with chopped cilantro leaves.