In a small bowl, whisk together the broth or water, soy sauce, sugar, Worcestershire sauce, and cornstarch, stirring constantly until the cornstarch dissolves. Heat a wok or skillet over medium-high heat. Add the oil and heat for 30 seconds. Add the ginger, garlic, and pepper flakes and stir-fry until fragrant, about 15 seconds. Add the cornstarch mixture and bring to a boil. Cook, stirring constantly to prevent lumps, until the sauce thickens slightly, about 1 1/2 minutes. Pour into a bowl.