Place the sliced beef in the slow cooker. Add the soy sauce, brown sugar, garlic, ginger, sesame oil, and red pepper flakes. Stir until the beef is coated.
Cover and cook on low for 6 to 8 hours until the beef is very tender.
About 30 minutes before serving, cook the jasmine rice according to the package directions.
Steam the broccoli florets until they are bright green and crisp-tender, about 5 minutes.
Divide the cooked rice among four containers. Top each with a portion of the beef and broccoli. Sprinkle with sliced green onions and sesame seeds.