There are many classes held in Hong Kong for making sweetheart cakes. The sweetheart cake, though it has such a long history, is still popular among many in Hong Kong and Mainland China. Many people in Hong Kong, as well as professional chefs, are reportedly modifying this pastry to make it more "modern" and better-tasting.
There are two legends that attempt to explain the origins of the Sweetheart cake. One tells the tale of a couple that lived a very poor life in imperial China. They loved each other and lived in a small village.
Suddenly, a mysterious disease spread. The husband's father became very sick. The couple spent all of their money in order to treat the man's father, but he was still sick. The wife sold herself as a slave in exchange for money to buy medicine for her father-in-law.
Once the husband learned about what his wife did, he made a cake filled with winter melon and with a crispy crust. His cake became so popular that he was able to earn enough money to buy his wife back.
There is another version where the man was eating at someone's house and recognized his wife's pastry and was reunited.