This place in Hung Hom selling (雞蛋仔) is very popular. Most of the time I pass by, there is a small crowd outside. Their 雞蛋仔 is crispy on the outside and soft inside.
The trick is simple. They use a fan to cool the 雞蛋仔 after they take it out of the pan, before giving it to you. Just like so many things in life, it is the attention to the details that distinguishes it from run-of-the-mill products.