1. Preheat oven to 350°F. Wrap cardamom pods, cinnamon stick, ginger, and cumin seed in small piece of cheesecloth and secure with kitchen twine. In heavy-bottomed Dutch oven, bring water, spice bundle, and 1 tablespoon salt to boil over medium-high heat; reduce to medium and simmer, partially covered, until spices have infused water, about 30 minutes.

2. Meanwhile, season both sides of chicken thighs with salt and pepper and set aside. Heat 3 tablespoons butter in 12-inch nonstick skillet over medium-high heat until foaming subsides; add half of onions and cook, stirring frequently, until soft and dark brown about edges, 10 to 12 minutes. Add half of jalapeños and garlic and cook, stirring frequently, until fragrant, about 2 minutes. Transfer onion mixture to medium bowl, wipe skillet clean with paper towels, and repeat with second batch of onions, jalapeños, and garlic. Transfer to bowl with rest of onion mixture, season lightly with salt, and set aside. Wipe out skillet with paper towels, return heat to medium-high, and place all eight chicken thighs skin side down in skillet; cook, without moving chicken, until well browned, about 6 to 8 minutes. Flip chicken and brown second side, 4 to 5 minutes longer; transfer chicken to plate and remove and discard skin. Tent with foil to keep warm.

3. If necessary, return spice-infused water to boil over high heat; stir in rice and cook 5 minutes, stirring occasionally. Drain rice through fine-mesh strainer, reserving 3 cups cooking liquid; discard spice bundle. Transfer rice to medium bowl; stir in saffron and currants (rice will turn splotchy yellow) and season with 1/4 teaspoon table salt. Spread half of rice evenly in bottom of now-empty Dutch oven using rubber spatula. Scatter half of onion mixture over rice, then place chicken thighs, skinned side up, on top of onions; add any accumulated chicken juices. Evenly sprinkle with cilantro and mint, scatter remaining onions over herbs, then cover with remaining rice; pour 1 1/2 cups reserved cooking liquid evenly over rice.

4. Cover Dutch oven and place in preheated oven. Cook for 30 minutes. Uncover and check bottom of pan. If dry, add up to 1 cup reserved cooking liquid. Cook about 20 minutes more or until rice is tender and chicken is cooked through. Run heatproof rubber spatula around inside rim of Dutch oven to loosen any affixed rice. Transfer chicken thighs to separate plate. Stir rice thoroughly. Using large serving spoon, spoon biryani into individual bowls, serving 1 chicken thigh per person.

Serves 8