Chicken, Olive, and Lemon Tagine (Djaj Mqualli)

Ingredients

• 3 tbsp. olive oil
• 6 whole chicken legs
• Kosher salt
• freshly ground black pepper
• 2 large yellow onions, sliced
• 2 tbsp. ground coriander
• 2 tsp. ground white pepper
• 2 tsp. ground ginger
• 1 tsp. ground turmeric
• 1⁄2 tsp. crushed saffron threads
• 1 1⁄2 cups chicken stock
• 6 oz. green olives, cracked
• 2 tbsp. unsalted butter
• 1 tbsp. finely chopped parsley
• 2 tsp. finely chopped cilantro
• 2 jarred preserved lemons, cut into slices