How to Make It
Preheat the oven to 400°. In a small saucepan, combine the cider vinegar, chicken stock, butter and maple syrup and bring to a boil. Cook over moderately high heat until reduced by half, about 15 minutes.
Meanwhile, in a large shallow roasting pan, toss the sweet potatoes, onions and chestnuts with the olive oil and thyme; season with salt and pepper. Tuck the beets among the other vegetables and roast for 20 minutes. Gently turn the vegetables, add the apples and roast for 20 minutes longer, or until all of the vegetables and the apples are tender and lightly browned. Add the sauce and toss gently. Transfer to a platter and serve.