Step 1

In a large bowl, cover rice with cold water and 1 tablespoon salt. Soak for 1 hour, then drain.

Step 2

Combine boiling water and saffron in a medium bowl. Whisk in 1 tablespoon salt and 6 tablespoons melted butter.

Step 3

In another bowl, whisk together yogurt and egg, then stir in half of saffron mixture. In yet another bowl, toss potato slices with 1 tablespoon saffron mixture to coat.

Step 4

Bring a large pot of water to a boil. Season with remaining 1 tablespoon salt. Boil rice until slightly tender but still not fully cooked, 5 minutes; drain.

Step 5

Grease a 10-inch non-stick pot with remaining 2 tablespoons melted butter. To the yogurt mixture, gently stir in 3 cups boiled rice until coated. Line the bottom of pot with potato slices, then spread coated rice over potatoes and up 1-inch around sides. Top with remaining rice, then drizzle remaining saffron mixture on top.

Step 6

Wrap a towel around pot lid and cover. Place over medium-high heat until you begin to hear rice sizzling, 4-5 minutes. Reduce heat to low and continue to cook until golden brown, 15-20 minutes; remove from heat. Place a platter over pot and invert so crispy rice is on top, then serve.