Marinade the meat in the teriyaki sauce the night before (or at the very least, two hours).
When ready to make, prepare the sauce first. In a medium bowl, combine all the sauce ingredients with a whisk until well mixed, and set aside.
Heat grape seed oil in a large skillet or wok, over medium heat. Add meat and cook, flipping once until browned, about five minutes.
Stir in broccoli and sauce mix until tender and slightly thicken, about 5 minutes.
Serve immediately over steamed white or brown rice.