3 medium baking potatoes, peeled and cut into 1-1/2-inch pieces
2 medium onions, cut into wedges
2 tablespoons butter, melted
4 teaspoons minced fresh thyme or 1 teaspoon dried thyme
Preheat oven to 375°. Place chicken, breast side up, in a 14-in. cast-iron or other ovenproof skillet. Rub with oil; sprinkle with 1/4 teaspoon salt and 1/4 teaspoon pepper. If desired, tie legs together with baker's twine. Bake, uncovered, 1 hour.
Arrange the carrots, celery, potatoes and onions around chicken. Combine butter and thyme; drizzle over chicken and vegetables. Sprinkle with remaining 1/4 teaspoon salt and 1/4 teaspoon pepper.
Cover and bake until a thermometer inserted in thickest part of thigh reads 170°-175° and vegetables are tender, 30-45 minutes.