
In a medium bowl, whisk together beef broth, soy sauce, oyster sauce, brown sugar, sesame oil and garlic.
Place beef into a 6-qt slow cooker. Add sauce mixture and gently toss to combine. Cover and cook on low heat for 90 minutes.
In a small bowl, whisk together 1/4 cup water and cornstarch.
Stir in cornstarch mixture and broccoli into the slow cooker. Cover and cook on high heat for an additional 30 minutes.
Serve immediately.