Cut beef against the grain, add salt, sugar, light soy sauce, ,white pepper, water, and cornstarch. Mix well until well combined. Then add vegetable cooking oil, remixing again. Set aside.
Prepare your serving pot, grease it with oil, and then spread the mustard greens in.
Heat the wok first, then reduce the heat. Add doubanjiang and chili sauce, and fry for 2-3 minutes over the lowest heat, stirring occasionally, until the oil turns red. Add garlic, dried chili pepper and Sichuan peppercorn.
Add the beef in. Quickly fry for around 30 seconds until the beef is almost cooked.
Then transfer all the content to the serving pot, add salt, light soy sauce, and sugar, and mix well. Cover the lid and heat for another 3 minutes. Enjoy! You need to stir it once or twice in the process.