Marinate the steak in the marinade while you prepare your veggies.
Heat 2 T. of oil in a pan (I use a large skillet) on HIGH HEAT. When your pan is piping hot, add the steak in a single layer. Let it sit there for 1-2 minutes without disturbing. Once it has browned nicely on one side, stir-fry it for another 1-2 minutes. Until it is cooked through. Remove from heat and set aside.
In the same pan on MED-HIGH heat, heat 1 T. oil and add your vegetables. Cook for 3-4 minutes (stirring constantly) or until the broccoli is slightly tender.
Combine your sauce ingredients and mix well to incorporate the cornstarch. Add the meat back into the pan with the vegetables. Pour the sauce into the pan and remove from the heat. Stir well. Since the pan is super hot, the sauce should thicken very quickly.
Serve over steamed white rice.
Notes
Store leftover stir-fry in an airtight container for 3-4 days.