A classic Indian meat preparation, Mutton Biryani features slow-braised meat in an aromatic spice-laden gravy. High in protein and deeply satisfying, it's a treasured family recipe.
Rinse the basmati rice in cold water until the water runs clear; soak in fresh water for 30 minutes, then drain.
Marinate the mutton with yogurt, half the ginger, half the garlic, half the ground spices (turmeric, coriander, cumin, chili powder), and 1 tsp salt for at least 1 hour (up to overnight in the refrigerator) for maximum flavor absorption.
Heat ghee and oil in a large heavy-bottomed pot over medium heat. Add cumin seeds, cardamom, cloves, bay leaves, and cinnamon; fry until aromatic (about 1 minute). Add sliced onions, cooking on medium-high until deeply golden and crisp (12-15 minutes), stirring to avoid burning.
Add remaining ginger and garlic, sauté 1 minute until fragrant. Stir in tomatoes, then cook until soft. Add marinated mutton and brown the meat for 5-7 minutes, then reduce heat to low, cover, and slow-cook for 45-60 minutes until the meat is tender and the oil separates.
While the mutton cooks, bring a large pot of water to a rolling boil; season with remaining salt, then cook the soaked rice until nearly tender (70% cooked, about 5-6 minutes). Drain immediately to avoid overcooking.
Layer: Spread half the cooked rice over the braised mutton in the pot, sprinkle with cilantro, mint, lemon juice, and garam masala. Top with the remaining rice. Soak saffron in warm milk for 5 minutes, then drizzle over rice for aroma and color.
Seal the pot with a tight-fitting lid or foil. Simmer (low heat) for 25-30 minutes to allow steam ('dum') to finish cooking and meld flavors. Turn off heat and let sit 10 minutes before serving. Gently fluff rice and serve hot.