Ottolenghi's Roast Chicken with Za'atar and Sumac

Name: Ottolenghi's Roast Chicken with Za'atar and Sumac
Prep time: 20 min
Cook time: 40 min
Total time: 1 h
Cuisine: Middle Eastern
Ingredients: 8 chicken thighs with skin and bones, trimmed of excess fat and loose skin; 2 red onions, thinly sliced; 1 lemon, thinly sliced; 2 large cloves of garlic, crushed; 5 tbsp olive oil, divided; 2 tablespoons za'atar plus more to taste; 1 tablespoon sumac; 1 teaspoon ground cinnamon; 1 cup chicken broth; 1 1/2 teaspoons salt, plus more to taste; 1/2 teaspoon freshly ground black pepper, plus more to taste; 6 tablespoons pine nuts; 1/4 cup chopped flat-leaf parsley