Preheat the oven to 400F.
Add the chicken, potatoes. and onions to a baking pan that has been sprayed with olive oil. Season generously with salt and pepper.
Mix together the marinade ingredients which is olive oil, za'atar, sumac, lemon juice, pomegranate molasses, honey, and 7 spice.
Pour the marinade over the top making sure to cover the chicken very well even under the skin and on both sides.
Sprinkle the chicken with more za'atar seasoning then cover the baking pan with foil and bake for 1hr 20 min covered. Uncover the last 5-10 minutes of baking.
The chicken should be super tender and lightly browned as well as the potatoes. Enjoy with rice and salad on the side or warm pita. There are so many flavors in that pan that pita will scoop up!