Slice and velvet the beef
12 minChill the beef in the freezer for 20 minutes to make it easier to slice thinly. Identify the direction of the grain and cut across it into 3 mm-thick slices; beef cut with the grain stays stringy when chewed. Put the slices in a bowl, add the soy sauce, vinegar, ginger, white pepper, and water, and massage by hand until all the liquid is absorbed. Mix in the cornstarch and sesame oil last.