Cut the steak into thin slices against the grain, this will ensure that the meat is tender. Cut the broccoli into small pieces and boil with a pinch of salt and a pinch of oil, for 2 minutes. Drain it out and rinse it under running water to stop the cooking process. Set aside.

In a large bowl, combine soy sauce, dark brown sugar, cornstarch, and hot water. Stir until well mixed.

Heat cooking oil in a wok or large frying pan over medium-high heat until very hot but not smoking. Add garlic and stir until fragrant, then add beef slices along with some black pepper. Stir-fry for 2 to 3 minutes until nicely browned on all sides but still rare in the middle.

Gradually pour the sauce mixture over the beef. Turn down the heat to medium-low, and let it simmer until the sauce is thickened.

Fold in pre-boiled broccoli, Stir-fry until cooked through, about 2 minutes. Remove from the heat.

Garnish with toasted white sesame seeds. Serve and enjoy!