In medium bowl whisk together 1 T soy sauce, ginger, cornstarch, and 1/2 t oil, add beef and toss to coat. Marinate at room temperature 10 minutes.
In a small bowl whisk together remaining soy sauce, vinegar, and sugar until sugar is dissolved.
Into large skillet or wok pour enough water to reach 1 inch up the side of the pan, bring to a boil over medium high heat and add broccoli. Cove and cook until broccoli is tender and bright green
, about 3 minutes.
Drain broccoli and transfer to a medium bowl.
Wipe out skillet place over high heat and add remaining oil, once hot add garlic and cook 15 seconds, stirring constantly. Draine bed from marinade and add in one layer to skillet and cook for 30 seconds on one side then flip and cook for another 30 seconds on the other side. Stir in soy vinegar mixture and cook 30 seconds to 1 minute until beef is cooked through. Add cooked broccoli and toss to coat. Serve immediately.