Before preparing the marinade for the beef, place the steak in the freezer for 30 minutes (this firms up the beef making it easier to slice thinly).
Mix the marinade ingredients together in a bowl and set aside.
Slice the beef with a cleaver or sharp knife into thin slices and mix with the marinade ingredients. Cover and chill in the fridge for up to 2 hours.
Meanwhile, prepare the black beans: rinse the fermented black beans in a tea strainer under a tap and place into a cup. Cover with water and soak for 15 to 20 minutes. Drain and rinse well. Chop very finely and set aside.
Combine all the sauce ingredients together and set aside.
When ready to cook, heat a wok with oil. Drain the meat from the marinade and pour the remaining marinade into the sauce ingredients.
When the wok is good and hot add the meat. Stir fry until cooked, remove with a slotted spoon and set aside.
Add the carrot, pepper and onion. Stir fry over high to medium heat for 7 to 8 minutes until softened but still retaining a bit of crunch. Adding splashes of water occasionally while stir frying - this aides with steam-cooking the vegetables. Add the black beans and cook for about 2 to 3 minutes, be careful not to burn.
Add the garlic and cook for a further 1 to 2 minutes. Return the beef to the wok along with the sauce. Stir well until thickens, 2 to 3 minutes. Mix in the sesame oil. Serve immediately with egg fried rice or noodles.