Add ¼ tsp saffron threads to a small bowl. Pour ¼ cup boiling water over the threads.
Separate the pulp from the skin of the preserved lemon. Finely chop the pulp and slice the skin very finely. Set aside.
In a large bowl, combine the ¼ cup chopped parsley, ¼ cup cilantro, lemon pulp, 4 garlic cloves, 2 tsp paprika, ¾ tsp ginger, ½ tsp cumin, ½ tsp coriander, ¼ tsp black pepper, 3 tbsp olive oil, and the saffron water.
Add 2.5 lbs chicken into the bowl and make sure that it is covered in the marinade and massage the marinade into the skin of the chicken. Cover the chicken and allow it to refrigerate for at least 2 hours or overnight.
Drizzle 2 tbsp olive oil in the bottom of a tagine or dutch oven. Add the 2 sliced onions and sprinkle with ½ tsp turmeric. Saute over medium-low heat for about 10 minutes until the onions are softened and translucent.
Add the marinated chicken into the dutch oven on top of the onions. Make sure to pour any remaining marinade into the pot.
Turn the stove to medium heat and add the tagine/dutch oven for 5 minutes until the liquid begins to simmer.
Reduce the heat to low and cook for about an hour, until the chicken is cooked to 165 degrees Fahrenheit.
After an hour, drizzle the chicken with the ½ tsp liquid from the preserved lemons. Add the ½ cup green olives and the sliced preserved lemon skins into the pot. If you want your chicken to be saltier, you can add more preserved lemon juice (it is very salty).
Cook, uncovered, for 15 minutes until the liquid evaporates slightly and the sauce thickens. Serve with crusty bread and enjoy!