Preheat the oven to 400°F (200°C).
In a large roasting pan or baking dish, toss the chicken pieces, potato wedges, and quartered onion with garlic, baharat, smoked paprika, cumin, salt, pepper, lemon juice, and olive oil.
Layer the vegetables evenly on the bottom of the pan, and arrange the chicken on top of the vegetables.
Pour the chicken stock into the pan around the edges.
Cover the pan tightly with foil and roast for 30 minutes.
Remove the foil and continue roasting for 25–30 minutes, until the chicken is golden and cooked through (165°F/74°C internal temperature) and the potatoes and onions are tender.
Optional crisping: For a crispier finish, broil for 2–3 minutes at the end.