In the crockpot, whisk together beef broth, soy sauce, dark brown sugar, sesame oil, and garlic.

Gently place your slices of beef in the liquid and toss to coat.

Turn crockpot on low and cook for 6 hours.

When done, in a small bowl, whisk together cornstartch and cooking liquid to create a slurry, pour into crockpot, stir to mix well. Cook on low for an additonal 30 minutes to thicken sauce.

Toss in broccoli florets then serve over white rice.