In a bowl, combine the beef broth, soy sauce, brown sugar, garlic, and ginger.
Place the beef chunks in the crockpot and pour the sauce mixture over them.
Stir to coat the beef evenly.
Cover and cook on low for 6-8 hours or high for 3-4 hours.
About 30 minutes before serving, mix the cornstarch with a little water to create a slurry.
Stir the slurry into the crockpot to thicken the sauce.
Add the broccoli florets, making sure they are submerged in the sauce.
Cover and cook for an additional 30 minutes until the broccoli is tender.
Taste and adjust seasoning if necessary.
Serve hot over cooked rice.