Place beef in the crock pot. Pour consomme' and oyster sauce on top of the beef. Cover, cook on low for 8 hours.
After 8 hours, In a small bowl Stir 2 tablespoons of cornstarch with water and mix until smooth. Add to the crock pot and stir with the beef. Cover and cook on high for 10 minutes until thickened.
Boil frozen broccoli florets until thawed. Drain water and add into the beef mixture. Toss gently to mix. Serve hot