Cut steak into thin 1.5 inch pieces.
In a large bowl, mix 2 tbsp cornstarch with 3 tbsp of water. Add the beef pieces and toss until coated with the cornstarch mixture.
In a small bowl, mix the remaining 1 tbsp cornstarch with soy sauce, garlic, ginger, and brown sugar substitute and set aside.
On medium heat, place a large nonstick sauté pan on the burner and add 1 tbsp of olive oil.
After the oil is hot, add the beef. Cook, stirring constantly, until it is nearly cooked through.
Remove the beef to a plate.
Add remaining 1 tbsp of olive oil to the sauté pan. Once it is hot, add the sliced onions and broccoli. Cook, stirring from time to time, until the broccoli is tender, about 7 minutes.
Return the beef back to the pan, add the mushrooms, and the prepared sauce.
Bring the mixture to a boil and cook, stirring constantly, for 1 minute.
Serve with cauliflower rice if you’re on Phase 3 of the HCG Diet (first 3 weeks of maintenance) or any type of weight loss program. Otherwise, any type of rice will do!