Here’s an informative article about the popularity of bubble waffles (aka egg puffs, egg waffles, gai daan zai), a Hong Kong treat. Author Adele Wong offers some of her thoughts on the tasty treat:
https://www.eater.com/2017/7/7/15928320/hong-kong-bubble-waffle-egglet-gai-daan-zai-ice-cream