Preparation

• Position a rack in the center of the oven and heat the oven to 400°F.

  In a medium saucepan, combine the orange juice and pomegranate juice. Bring to a boil over medium heat and reduce to 1/4 cup, about 15 minutes. Add 1/2 tsp. of the thyme, the cinnamon, and 1/4 tsp. pepper. Divide the mixture between two small bowls. To one bowl add 2 tsp. of the oil and 1/2 tsp. salt. To the other add the chicken broth, all but 1 tsp. of the orange zest, and 1/4 tsp. salt.

  Scatter the sweet potatoes, parsnips, and onion over the bottom of a metal, glass, or ceramic baking dish that measures about 10x15x2 inches. Toss with the remaining 4 tsp. of oil and 1 tsp. thyme. Arrange the chicken pieces, skin side up, on top of the vegetables and brush with all of the juice-oil mixture. Roast for 30 minutes.

  Remove the pan from the oven and reduce the temperature to 375°F. Pour the juice-broth mixture around the chicken pieces and scatter the walnuts around the chicken. Return the pan to the oven and roast until the vegetables are tender and an instant-read thermometer registers 165°F in several pieces of chicken, 20 to 30 minutes.

  Transfer the chicken to a warmed platter. Use a slotted spoon to arrange the vegetables and walnuts around the chicken. Sprinkle the vegetables with a little salt and sprinkle the remaining orange zest over all. Tilt the roasting pan so that the juices gather in one corner. With a large, shallow spoon, skim as much fat as possible from the pan sauce. Season the sauce to taste with salt and pepper and pour into a pitcher to pass at the table.