Shrimp Biryani is a layered rice dish and one of many recipes Zinobia Lakhani learned from her late mother-in-law. To toast saffron, stir in a small dry frying pan over medium heat until fragrant, 30 to 60 seconds.
2 tablespoons vegetable oil
1/2 cup chopped raw cashews
6 whole cardamom pods, crushed
4 dried bay leaves
1 cinnamon stick (about 2 in.)
1 teaspoon cumin seeds
2 onions (1 lb. total), peeled and chopped
1 tablespoon minced garlic
1 1/2 pounds peeled, deveined shrimp (31 to 40 per lb.), rinsed
1/2 teaspoon each chili powder, turmeric, and pepper
Pour 1 tablespoon oil into a 10- to 12-inch pan over medium heat. Add cashews, cardamom, bay leaves, cinnamon stick, and cumin seeds; stir until fragrant, about 2 minutes. Pour into a bowl.
In pan, heat remaining tablespoon oil over medium-high heat. Add onions and garlic; stir until limp, 5 to 8 minutes.
Stir in shrimp, chili powder, turmeric, pepper, 1/2 teaspoon salt, and nut-spice mixture. Cook, stirring frequently, just until shrimp begin to turn pink, 2 to 3 minutes. Reduce heat to medium; stir in yogurt. Cook, stirring often, until most liquid has evaporated, about 15 minutes. Remove bay leaves and cinnamon stick.
Meanwhile, in a 5- to 6-quart pan over high heat, bring 2 1/2 quarts water to a boil. Add rice; boil uncovered until almost tender, 7 to 8 minutes. Drain and pour into a bowl. Stir in the lemon juice and salt to taste.
In a buttered 3 1/2-quart baking dish, spread about 1/3 of rice mixture level. Top with 1/2 shrimp mixture, spreading level. Repeat layers, ending with rice. Sprinkle evenly with saffron threads. Cover tightly with foil.
Bake biryani in a 350° oven until center is hot and rice is tender to bite, 20 to 25 minutes. Serve immediately, with raita.