Step 1

In a medium bowl, combine the rice with enough water to cover by about 1 inch. Set aside at room temperature for at least 30 minutes or up 12 hours. Drain the rice in a fine-mesh sieve, then rinse under cool running water and drain again.

Step 2

In a small bowl, stir together the saffron and boiling water; set aside. Heat the oven to 400°F with a rack in the lowest position. Brush the bottom and sides of a 9-inch deep-dish glass pie plate with 2 tablespoons of the oil.

Step 3

In a medium bowl, combine the chicken, remaining 1 tablespoon oil, 1 teaspoon of the lemon zest, the garlic, ½ teaspoon each salt and pepper and 1 tablespoon of the saffron water. Stir until the chicken is evenly coated; set aside at room temperature.

Step 4

In a large saucepan, bring 2 quarts water to a boil. Meanwhile, in a large bowl, combine the yogurt, egg yolk, remaining 2 teaspoons lemon zest and remaining saffron water; whisk until well combined.

Step 5

When the water reaches a boil, stir in the rice and 2 tablespoons salt. Return to a boil and cook, stirring occasionally, for 5 minutes; it will not be fully cooked. Drain the rice in a fine-holed colander or large fine-mesh sieve, shaking to remove excess water. Add the rice to the yogurt mixture and stir until thoroughly combined.

Step 6

Add about 1½ cups rice mixture to the prepared pie plate, gently pressing it into an even layer over the bottom and about halfway up the sides. Stir the chicken mixture and the currants into the remaining rice mixture, then transfer to the pie plate and distribute in an even layer; do not compact the rice mixture. Drizzle the melted butter evenly over top. Cover tightly with foil and bake for 1 hour. Carefully remove the foil and continue to bake until the bottom is golden brown, about 10 minutes. Remove from the oven and let rest for about 5 minutes.

Step 7

Run a silicone spatula around the edge to loosen the rice from the pie plate. Invert a serving platter over the pie plate. Holding the platter against the pie plate, carefully invert the two together. Carefully remove the pie plate. Sprinkle with parsley and pistachios.