The white part in the stir-fried yellow beef with cooking smoke is hydrangea. Hydrangea is a nutritious fungus that looks like a hydrangea. It is also called "snow lotus fungus" and its taste is very delicious. During the cooking process, the hydrangeas absorb the broth and flavor of the beef, making it richer and more flavorful.

The above information is for reference only. If you have any questions or want to know more about smoked stir-fried yellow beef, you can consult professional chefs or related professionals.