In a bowl, mix the broth, sherry, soy sauce, cider vinegar, cornstarch, sugar, dry mustard, and salt.
Heat the oil in a skillet over medium heat. Mix the asparagus into the skillet, coating with the oil. Cook and stir 5 minutes, until tender but firm. Pour the broth mixture over the asparagus, and continue cooking 5 minutes, until thickened and heated through.