Place the meat in a ziplock bag. Stir the cornstarch and cold water in a small bowl. Add this to the bag with the meat. Marinade for at least 20-30 minutes.
Heat the vegetable oil in a large skillet over medium high heat. Add the chopped broccoli onto the skillet. Sauté covered for 3-4 minutes until slightly tender. Then stir in the marinated beef. Sauté uncovered for an additional 3-4 minutes until the beef is cooked through and the broccoli is tender.
Combine all the sauce ingredients together in a small bowl. Pour the sauce over the beef and vegetables and toss to combine. Heat for 1 minute to make sure that all the flavors are combined and heated through.
Remove from heat, serve warm over cooked rice and enjoy!
