Preparation

• Position a rack in the center of the oven, and heat the oven to 425°F. Put the rutabagas, onion, and carrots in a large bowl, and toss with 2 Tbs. of the oil, 1-1/2 tsp. salt, and half of the thyme. Transfer to a 13×17-inch roasting pan. In the same bowl, toss the sweet potatoes with the remaining 1 Tbs. oil. Set aside.
• Roast the vegetables for 10 minutes. Remove the pan from the oven, add the sweet potatoes, and toss. Return to the oven, tossing again after 20 minutes. Roast the vegetables until they begin to brown and become tender, about 30 minutes total.
• Meanwhile, in a small saucepan, boil the cider over medium-high heat, stirring occasionally, until reduced to about 1/2 cup, 10 to 15 minutes. Remove from the heat, add the brown sugar, and stir until it dissolves.
• Pour the glaze over the vegetables, and toss to coat. Return to the oven and roast, tossing every 5 minutes or so, until the vegetables are nicely browned and tender, about 25 minutes.
• Serve immediately, sprinkled generously with pepper and the remaining 1 tsp. thyme.