How to Make the Ultimate Umami-Bomb Vegetarian Demi-Glace
1 Granny Smith apple—peeled, halved, cored and sliced 1/16 inch thick on a mandoline
4 Belgian endives, halved lengthwise
1 tablespoon unsalted butter
1 tablespoon vegetable oil
Salt and freshly ground pepper
1/2 cup water
Carefully tuck 6 apple slices between the leaves in each endive half. In a large skillet, melt the butter in the oil over high heat. Add the endives, cut sides down, and cook over moderate heat until nicely browned, about 6 minutes. Carefully turn the endives. Season with salt and pepper and add the water to the skillet. Cover and simmer over low heat until the endives are tender, 12 to 15 minutes. Uncover and cook until the liquid has evaporated. Serve hot.