Preheat oven to 375°.
Combine hoisin through garlic in a large zip-top plastic bag. Add pork; seal and marinate in refrigerator 1 hour, turning bag occasionally. Remove pork from bag, reserving 1/4 cup marinade. Discard remaining marinade.
Place pork on a broiler pan coated with cooking spray; insert meat thermometer into thickest portion of pork. Bake at 375° for 35 minutes or until thermometer registers 155°. Let stand 5 minutes. Cut pork in half lengthwise. Cut each half crosswise into 1/4-inch-thick slices; keep warm.
To prepare sauce, combine chicken broth through sesame oil in a bowl. Set aside.
To prepare stir-fry, heat vegetable oil in a wok or large Dutch oven over high heat. Add onions, garlic, and ginger; stir-fry 10 seconds. Add reserved marinade, oyster sauce, and broccoli; bring to a boil over high heat; cook 1 1/2 minutes or until slightly thickened, stirring constantly. Stir in pork; cook 1 minute or until thoroughly heated. Serve over rice.