How to Make the Ultimate Umami-Bomb Vegetarian Demi-Glace
1/2 cup cider vinegar
1/2 cup chicken or vegetable stock or canned low-sodium broth
2 tablespoons unsalted butter
1 tablespoon pure maple syrup
2 large sweet potatoes, peeled and cut into 2-inch chunks
2 medium red onions, each cut into 8 wedges through the core
1 cup vacuum-packed whole chestnuts (6 ounces)
1/4 cup extra-virgin olive oil
1 tablespoon thyme leaves
Salt and freshly ground pepper
2 medium beets, peeled and cut into 2-inch chunks
2 large tart apples, such as Granny Smith, cored and cut into eighths
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.