Cut the beef neck into bite-sized pieces.
Rinse the bean sprouts thoroughly and set aside.
Heat cooking oil in a pan over medium-high heat.
Add the beef neck pieces first and stir-fry them.
Once the beef is cooked, add the bean sprouts and stir-fry together.
Season with soy sauce, salt, and pepper.
When the bean sprouts have wilted, turn off the heat.
Transfer to a plate and serve.