Preheat the oven to 375°F (190°C).
Prepare the chicken: cut the whole chicken into pieces (or use breasts/drums). Remove skin if you prefer. Make several small cuts in each piece so flavors can penetrate.
Season the chicken: rub the chicken pieces with the baharat (1 teaspoon), some of the olive oil, and some of the 2 teaspoons salt. Reserve the remaining salt and olive oil for the vegetables and cooking.
Prepare the vegetables: peel the potatoes and cut into disks; peel the carrots and cut into rounds; if using the zucchini, peel if desired and cut into rounds; peel and cut the onion into medium pieces; crush or finely chop the 3 garlic cloves.
Lightly salt the potato slices with some of the reserved salt.
In a large pot or skillet over medium heat, add about 1 tablespoon of the olive oil (from the 2 tablespoons). When hot, add the potato slices and brown them lightly on both sides (about 2–4 minutes per side). Remove the potatoes and set aside.
In the same pot, add the remaining olive oil if the pan looks dry. Add the chopped onion and sauté over medium heat until soft and lightly browned (about 5–7 minutes). Add the crushed garlic and cook 20–30 seconds until fragrant.
Add the seasoned chicken pieces to the pot with the onion and garlic and brown the chicken lightly on all sides (2–4 minutes just to color).
Transfer to an ovenproof dish: place the browned chicken pieces with the onion and garlic in the bottom of the dish. Arrange the browned potato slices on top and add the carrots and zucchini (if using) around/on top of the potatoes.
Pour 1 cup chicken broth or water into the dish (pour around the edges so you don’t wash off the seasoning). Sprinkle any remaining salt as needed and add the dried herbs from the ingredient list.
Cover the dish with a lid or tightly with foil and bake in the preheated oven for about 20–25 minutes, or until the chicken is cooked through and the potatoes are tender.
If you want a browned top, remove the cover and place the dish under the broiler for about 4–5 minutes until the top is browned to your liking. Remove from oven and let rest a few minutes before serving.