Cut the beef against the grain into thin slices. Then cut into shreds.
Mix the beef with all the seasonings expect cornstarch. Marinating for 15 minutes. Then mix cornstarch in. Mix well.
Add around 1 tablespoon of cooking oil in wok and fry celery for 1 minutes until just cooked.
Heat the wok until hot firstly. Then place 1 tablespoon of oil and add garlic, ginger, scallion and pickled peppers. Fry until aromatic.
Push all the content in the wok to one edge of the wok, add another 2 tablespoon of cooking oil in center and spread the beef shreds in. Gently fry When the beef begin to change color on surface, place 1 tablespoon of doubanjiang in.
Add dark soy sauce, celery and salt if necessary. Mix well quickly. Serve hot!
If you cannot get pickled peppers, use fresh chopped peppers. But the amount of fresh peppers should be halved. Otherwise, the final dish might be overwhelming spicy.
In order to create a slightly sour taste, add around 2 teaspoons of black vinegar along with dark soy sauce.