Grind the saffron threads into a powder using a mortar and pestle, or crush them between your fingers into a bowl. Add the cumin, paprika, turmeric, and cayenne, and mix well.

Season the chicken pieces with kosher salt and a few grinds of black pepper. Rub the spice mixture evenly over the chicken.

In a large heavy-bottomed pot, heat the olive oil over medium heat. Sauté the onion, stirring occasionally, until translucent, about 5 minutes. Add the garlic and cook until the onions are lightly browned, about 2-3 minutes.

Nestle the chicken pieces into the pot in a single layer. Pour in the chicken stock and bring to a gentle simmer. Cook uncovered over medium heat for 1 hour.

Meanwhile, remove the pulp from the preserved lemons and discard. Thinly slice the peels.

After 1 hour, add the lemon peel, cilantro, and parsley to the pot. Stir gently to combine. Reduce the heat to low and simmer uncovered for another 1 hour and 15 minutes, stirring occasionally, adding more stock if needed to keep the chicken mostly submerged.

Once the chicken is tender and cooked through, carefully transfer it to a serving dish, leaving the sauce in the pot.

Add the olives to the pot and simmer the sauce over medium heat for about 5 minutes, until slightly reduced. Taste and adjust with salt and pepper if needed.

Pour the sauce over the chicken and garnish with fresh lemon slices and a few sprigs of cilantro and parsley.

Leftovers can be stored in an airtight container in the refrigerator for up to 4 days.