Using a smooth mortar and pestle, ground the saffron threads to a fine powder. Add the saffron powder to a small bowl and add the water to bloom the saffron. Stir and set aside.
Combine the chicken and 4 tablespoons of the saffron water mixture in a large mixing bowl, gently toss, cover, and place in the refrigerator for 1 hour. The chicken will continue to be infused with saffron’s bright yellow-orange color, aroma, and flavor.
Combine the yogurt, onion, lime juice, olive oil, salt, and pepper in a separate medium-sized mixing bowl. Transfer them to the large mixing bowl with the chicken and saffron mixture.
Mix well using a spatula, cover, and place the chicken in the refrigerator to marinate for a minimum of 2 hours, but preferably overnight.
Begin preparing your charcoal or gas grill well in advance to make sure the grill is hot and ready by the time you are ready to grill the chicken.
Remove the chicken from the fridge and push the metal or previously soaked wooden skewers one by one through the chicken pieces. The number of pieces on each skewer will depend on the length of your skewer and your choice of charcoal or gas grill. A good rule of thumb is to make sure the chicken pieces are not overcrowded on the skewer while also leaving some space at either end of the skewer.
Place the skewers on a large platter or a baking sheet. Gently tap the skewers against the tray to shake off any excess marinade.
Be sure to discard the remaining marinade to avoid any risk of food contamination.
Prepare the baste by mixing the gently melted butter, the remaining 2 tablespoons of saffron water, and the fresh lime juice.
Place the skewers on the grill and cook the kebabs for about 4-5 minutes on each side, basting frequently. The grilling time will vary depending on the temperature and strength of your gas grill.
Remove the kebabs from the grill and place them on a clean, unused platter once the internal temperature of the chicken pieces has reached 165°F.
Serve the Joojeh Kabob with grilled vegetables, flatbread of your choice, or a pot of steamed basmati rice.