Prepare the marinade: in a large bowl combine Plain Yogurt with Ginger-Garlic Paste, finely chopped Green Chilies, Kashmiri Red Chili Powder, Turmeric Powder, Garam Masala, Fine Salt and Lemon Juice. Add the Bone-in Lamb Pieces, toss to coat thoroughly, cover and refrigerate at least 1 hour (overnight for best flavor).
Heat a heavy, wide pot over medium-high heat and add Neutral Oil and a few tablespoons of Ghee. When hot, add whole spices—Bay Leaves, Green Cardamom Pods, Black Cardamom Pods, Cloves, Cinnamon Stick, Star Anise and Shah Jeera—and sauté briefly until aromatic.
Add thinly sliced Onions to the spiced oil and fry, stirring, until deep golden brown; remove about one third and set aside for garnish. Push the rest of the onions to the side, add the marinated lamb and sear on all sides until browned.
Pour in enough Water to just cover the lamb, reduce heat to low, cover and simmer gently until the meat is tender (about 45–60 minutes, depending on cut). Stir in half of the jarred Fried Onions into the cooked meat for extra depth, then check seasoning and adjust.
While the lamb is simmering, rinse and soak the Aged Basmati Rice for 20–30 minutes. Bring a large pot of water to a rolling boil, season with Salt, add a couple of whole spices if you like, then parboil the rice until it is about 70–80% cooked. Drain and set aside.
Bloom the saffron by crushing a pinch of Saffron Threads and stirring them into warm Warm Milk; set aside so the color and aroma infuse.
Assemble the biryani for dum: remove about half the gravy from the lamb pot if it’s very wet so layers will form cleanly. Spread a layer of half the parboiled rice over the lamb, drizzle with a little Ghee, sprinkle a handful of Mint Leaves and Cilantro Leaves and scatter some of the reserved fried onions. Spoon a few tablespoons of the saffron milk over the rice and a few drops of Kewra Water or Rose Water for floral aroma.
Repeat with the remaining rice to form a top layer, then finish with the remaining fried onions (Fried Onions), a final drizzle of ghee and another light sprinkle of mint and cilantro.
Seal the pot (cover with a tight-fitting lid or seal with dough) and cook on the lowest heat possible for 20–30 minutes to steam (dum) so flavors marry and rice finishes cooking. Let rest 10 minutes off the heat before gently fluffing the layers with a fork.
Serve hot, scooping through the layers so each portion has tender lamb, fragrant rice and crunchy fried onions; accompany with cooling raita or a simple salad if desired.
