Whisk together 3/4 cup beef broth, cornstarch, soy sauce, ginger, sugar, and pepper in a small bowl.

Heat oil in a large skillet or wok over high heat.

Add flank steak and crushed garlic cloves and saute for 2-3 minutes, until almost cooked.

Remove beef and set aside.

Add mushrooms, cabbage, sliced onion, and 2 tablespoons beef broth to the skillet.

Cook and stir for 4-6 minutes, until tender-crisp.

Pour the soy sauce mixture into the skillet with the vegetables and cook for 2 minutes, stirring until thickened.

Stir in the beef and heat through before serving.