Dissolve cornstarch in 1 tablespoon broth in small bowl. Set aside. Heat oil in wok or heavy large skillet over high heat. Add garlic and sauté until golden, about 1 minute. Add cabbage and soy sauce and stir-fry until cabbage is tender, about 1 minute. Add remaining 2 tablespoons broth, vinegar and sugar to wok and continue to stir-fry 1 minute. Add green onions and cornstarch mixture and continue to stir-fry until cabbage is coated and slightly brown, 1 minute.