Add yogurt, lime zest and juice, salt, paprika, cumin, coriander, cayenne, white pepper, cardamom, cinnamon, and allspice for marinade to a large mixing bowl;
whisk to combine.
Make one or two slits into each piece of dark chicken meat, down to the bone. Add chicken parts to the yogurt marinade and toss very thoroughly.
Wrap in plastic wrap and marinate in the refrigerator for 4 to 8 hours.
Preheat the oven to 450°F/230°C/Gas Mark 8. Lightly grease a 9x13-inch casserole dish.
Grind saffron in a mortar with a pestle. Pour in 1/4 cup chicken broth and stir to combine.
Combine unsalted butter and salt in a saucepan; pour in remaining 2 cups chicken broth and chicken broth-saffron mixture. Bring to a boil over high heat.
Add basmati rice and stir to combine. Reduce heat to low
, cover tightly
, and let simmer gently for exactly 15 minutes; do not disturb while cooking.
Turn off the heat and let rest for 10 minutes.
While the rice is still hot, transfer it into the prepared casserole dish. Use a fork to fluff the rice while gently spreading into an even layer.
Place the chicken pieces, skin-side up, on top of rice. Drizzle with olive oil and sprinkle with salt.
Roast in the center of the preheated oven until chicken is no longer pink in the centers and juices run clear, about 45 minutes.
An instant-read thermometer inserted into the thickest part of the thigh, near the bone, should read 165°F (74°C).
While chicken is in the oven, mix yogurt, garlic, green onions, mint, cilantro, salt, and water
together for sauce.
Reserve in the refrigerator until needed. Serve chicken and rice on a plate and top with sauce.
* The sauce is not optional!