Partially freeze pork; slice across grain into 1/4-inch slices. Clean broccoli, slice stalks into 1/4-inch slices; cut off the flowerettes. Remove stem and seeds from pepper and cut into thin strips. Set aside.

Combine chicken broth, cornstarch, oyster-flavored sauce, soy sauce, and ginger; set aside. Pour oil around top of preheated wok to cover sides. Heat oil over medium-high heat. Add pork, broccoli stalks, pepper and garlic; stir-fry 4 minutes or until pork is browned. Add broccoli flowerettes, mushrooms and onion; stir-fry 2 minutes.

Stir chicken broth mixture; gradually add to wok, mix well. Cook 3 minutes or until thickened and bubbly, stirring constantly. Serve over hot cooked rice, if desired.