In a large bowl big enough to fit the whole chicken, whisk together the salt, sumac, za’atar, pepper and olive oil. Stir in the garlic until well combined.

Place the chicken in the bowl and toss to coat with the marinade. I rub the chicken with the marinade with my hands. Carefully separate the skin from the chicken breast meat, sliding your fingers to separate the skin as far down as you can go, but trying not to tear the skin. Rub the marinade under the loosened skin and directly onto the meat as evenly as possible. Cover the bowl and refrigerate for at least 6 hours or overnight. Remove chicken from the fridge an hour before roasting.

Preheat oven to 425 degrees or 400 degrees convection.

Arrange the onion slices in one layer in a roasting pan or rimmed baking sheet that is just big enough to fit the chicken. Top the onions with herbs and garlic from the marinade. Place the chicken breastside up over the onions, herbs and garlic and scrape out any marinade from the bowl over the chicken. Lightly grease potatoes with oil and sprinkle with a pinch of salt and arrange around the chicken. Roast chicken for 25 minutes.

Pour the white wine into the pan (not on the chicken) and add the lemon halves to the pan. Roast for another 25-35 minutes or until temperature of breast is 160 degrees. Allow to sit covered out of the oven for 5-10 minutes before carving. Discard herbs and squeeze roasted lemon halves over chicken before serving.