1. Rinse the chicken and pat dry. Trim off excess fat.

2. Combine the sumac, spices, and salt. Set aside 2 teaspoons and mix the rest with the lemon juice. Rub into the chicken flesh and marinate up to 1 day.

3. Place the onions in a large skillet, toss with 1-1/2 tablespoons of the olive oil, half the chicken stock, reserved spices, and a pinch of salt. Cover and cook gently 30 minutes. (Up to this point, the dish can be prepared 1 day in advance.)

4. Bring the chicken to room temperature and preheat the oven to 400 degrees F.

5. Place the chicken, skin side down, on a nonstick baking sheet. Divide the onions into 4 parts and spread them over the chicken; cover with foil and bake 20 minutes.

6. Lightly brush a large ovenproof serving dish with the remaining oil. Scatter the torn bread in one or two layers on the bottom; sprinkle with the remaining chicken stock and carefully flip the chicken-and-onion quarters onto the bread so that the skin side is up. Return to the oven and bake 20 minutes, until tender and crispy brown. Serve at once with a sprinkling of the pine nuts.