When Hong Kong people celebrate birthday at Chinese restaurant, we like to order ”Shou Tao Bao” 壽桃包, literally means Longevity Peach Bun which is actually a steamed bun with lotus seed stuffing
Shou Tao is a fictional fruit. According to Chinese folk legends, these peaches ripen every thousands of years, and give immortality to humans when consumed. Thus Chinese people make the buns in the Peach shape for auspicious meaning when celebrate birthday.
Usually Shou Tao Buns can be found in big Chinese restaurants in Hong Kong and Macao. Some restaurants may require pre-order the day before; some can just order when dine-in, depends on the restaurants. Usually people would order one Shou Tao Bun for each person.
So it happens that you are celebrating birthday while visiting Hong Kong, try ordering Shou Tao Bun in Chinese restaurant. Or sometimes they may be available in some Chinese restaurants in China Town overseas too.