Cube beef chuck roast.
Add the beef chuck roast, beef broth, soy sauce, brown sugar, sesame oil, and minced garlic into the slow cooker. Sprinkle in pepper, salt, and onion powder.
Cook on High for 2 ½ - 3 ½ hours or on Low for 5 - 6 hours.
An hour before the slow cooker is done, mix equal parts cornstarch and sauce from the slow cooker and add slurry back in to the slow cooker.
30 minutes before the slow cooker is done, add in the frozen broccoli.
Serve over rice.