Combine the sauce ingredients

• Whisk the beef broth, soy sauce, brown sugar, sesame oil and garlic together in a bowl.

Load the slow cooker

• Place the sliced beef in the slow cooker and pour the sauce over it.
• Stir so the meat is well coated.

Cook the beef

• Cover and cook on high for 2.5 to 3.5 hours, or on low for 5 to 6 hours.

Thicken the sauce

• An hour before the end of cooking, mix the cornstarch with some of the cooking sauce until smooth.
• Stir the slurry back into the slow cooker and continue cooking.

Add the broccoli

• Thirty minutes before the end of cooking, add the frozen broccoli and stir gently.
• Finish cooking until the broccoli is tender and the sauce has thickened.

Serve

• Spoon the beef and broccoli with plenty of sauce over rice or noodles.