In a bowl, mix soy sauce, broth, sesame oil, and cornstarch. Set aside.
Place Chinese broccoli on a cutting board and slice 2 inches off the stems.
In a large wok or deep pan over high heat, add vegetable oil. When the oil is hot, add Chinese broccoli and saute for 5 minutes, tossing the broccoli every minute or so.
Add garlic, toss and cook for 1 minute.
Add sauce and cook for 1 minute, or until most of the sauce has evaporated.