Step 1

Place the lamb in a 1 gallon (3.8L) ziptop bag. In a medium bowl, mix the yogurt, garlic, ginger, and 1 1/2 teaspoons salt until combined, pour the yogurt mixture over the lamb, seal the bag, and shake the bag to coat the lamb well. Leave the ziptop bag in the refrigerator to marinate overnight.

Step 2

Heat 1/4 cup (60ml) ghee or oil in a Dutch oven or saucepan with a heavy bottom over medium heat. Add the onions, season with a pinch of salt, and cook, stirring occasionally, until the onions caramelize and turn dark brown (but not black), about 25 to 30 minutes.

Step 3

Reduce the heat to low. Remove half of the caramelized onions and reserve to use as garnish for the biryani. Add 3 green cardamom pods, cinnamon, cloves, bay leaves, garam masala, Kashmiri chili, mace, and turmeric, and sauté just until spices become fragrant, 30 to 45 seconds. Add the lamb along with the yogurt marinade, the water or stock, and the cilantro, mint, and green chili. Stir to mix well, increase the heat to medium-high, and bring liquid to a boil. Reduce heat to low, cover with lid, and cook for 30 to 45 minutes, stirring occasionally, until the lamb is completely tender.

Step 4

Meanwhile, as the lamb cooks, prepare the rice. Pick over the the rice for any debris, then place it in a fine mesh strainer and rinse under cold running water, until the runoff is no longer cloudy; drain well. Place the rice in a bowl and cover with 4 cups (960ml) water and let stand for 30 minutes. Strain the rice, discarding soaking water. In a large saucepan, combine rice with 4 cups cold water, lemon juice, the remaining 1 1/2 teaspoons kosher salt, the remaining 2 green cardamom pods, and the remaining 2 teaspoons of ghee or oil and bring to a boil over medium heat. Boil for 2 minutes and then strain the rice; discard cooking water. It will be partially cooked—if you break a grain of rice, you will see an outer translucent ring and a tiny, opaque inner ring.

Step 5

When the lamb is tender, remove lid and increase the heat to medium, stirring often to prevent scorching, and cook until the liquid starts to thicken and reduces to about 1 1/2 cups (360ml), about 5 minutes. Remove from heat. Using a clean, large wooden spoon or spatula, spread the rice out in an even layer over the meat in the Dutch oven.

Step 6

Set oven rack at the middle position and heat the oven to 350°F (180°C). Place half the saffron threads in a mortar and pestle and grind to a fine powder. In a small saucepan placed over low heat, warm the milk just until it starts to bubble, then turn off the heat. Add the ground saffron and remaining saffron strands to the hot milk and let steep for 10 minutes.

Step 7

Sprinkle the saffron-infused milk over the rice, followed by the rosewater and the pandan water. Garnish the top of the rice with the reserved caramelized onions. Cover the Dutch oven with two sheets of aluminum foil and crimp the overhang to form a tight seal, place the lid over the foil, and place the Dutch oven in the preheated oven for 20 minutes to let the rice steam. Remove from the oven and let stand for 5 minutes. Uncover the pot and carefully peel off the aluminum seal. Use a fork to loosen the rice a little and serve immediately straight from the Dutch oven. Alternatively, biryani can be transferred to a platter and served.