About crispiness for 'crispy beef' recipe---

I have been asked by a few friends why the beef is not crispy enough. -- here is the trick I learned from my uncle, who is a great 'home chef'. :) 


First, for coating the beef pieces, use only egg white, which is better for crispness; 


add couple of spoon of corn starch mix with plain flour; when deep frying ...it, wait until the oil is very very hot (like 100 degree) to put coated beef pieces in; 


and the last, this is my uncle's trick -- after frying, leave them on a plate for a little while, let it cool down a little bit, then put back to quick fry again.. here it will be crispy. 


but when you make the sauce, leave to the very last minute to put fried beef pieces in, once the sauce coated on the beef, quickly take them out onto a plate. hope this helps. :))