Start by slicing the meat into 5 mm (0.2") thick slices. Make sure to cut against the grain to avoid a chewy bite.
Soak the slices in cold water for 1 minute to remove the blood, then squeeze all the water out by hand.
Marinate the beef with the white pepper, light soy sauce, dark soy sauce, oyster sauce, Shaoxing rice wine, salt, sugar and chicken bouillon powder. Mix in well for until it is sticky to the touch. There also should be no excess water in the bowl.
Pour in the egg white and mix, then add the corn starch and stir until combined.
Add in 3 tbsp oil and mix until well incorporated. This will prevent the beef slices from sticking to each other when cooking.
Add 3 tbsp oil into a hot wok and fry the beef for 1-2 minutes or until roughly 80% cooked. You'll be tossing it in with the vegetables later, so there's no need to overcook it.
Replace the wok with 2 tbsp new oil (or reuse the same one) and stir fry the garlic, onion, ginger and bell peppers for 2 minutes or until fragrant then mix in the black pepper paste.
Pour the cooked beef in and stir fry for another 2 minutes, then plate.
Serve immediately with rice or noodles!