“Wait, it doesn’t flow.”
Zolima CityMag photographer Nicolas Petit is ready to capture a creamy egg custard bun (naai5 wong4 baau1 奶黃包) just broken open. This is one of Hong Kong’s favourite dim sum treats, but he is surprised to find that bright yellow lava isn’t oozing out from the centre. That’s because he is actually expecting something else: a lava custard bun (lau4 saa1 naai5 wong4 baau1 流沙奶黃包), which is commonly found in modern Chinese restaurants and dim sum chains.
But the lava bun is a usurper. In more traditional tea houses like Lin Heung in Sheung Wan—founded in 1889 in Guangzhou and relocated to Hong Kong in 1926—it’s the original creamy version that comes standard. But maybe not for much longer.
Like a lot of traditional Chinese buns, egg custard buns are steamed white Chinese buns (tong4 beng2 唐餅), whose dough contains flour, yeast, sugar and water. Depending on the texture and proportion of ingredients, Chinese buns can be sweet (such as egg custard buns or lotus seed paste buns) or savoury (like char siu buns and little chicken buns). Ammonia carbonate is added to the dough of savoury Chinese buns, which makes them less stretchy and more crumbly. When they are steamed, their folded opening bursts open like ruffles, which is known among dim sum makers as “a smiley mouth.” Conversely, the sweet ones are indicated by their smoother texture, created by adding more yeast to the dough, allowing it to rise gently.
While it may seem like a traditional bun, the filling of a creamy custard bun sets it apart. Common in various European cuisines, custard is made by cooking milk or cream with egg yolk until the mixture thickens. Sometimes flour, cornstarch or gelatin is added. Wong Kam-shing, a dim sum chef at Lin Heung, who has been in the Chinese restaurant industry for 51 years, says the custard buns are relative newcomers to the dim sum scene, some of whose dishes can be traced back to Hong Kong’s very first tea houses in the 19th century. Lin Heung began serving the custard buns in 1996.
He says it is “highly likely” that the buns were inspired by Japanese mochi, which are glutinous rice cakes with sweet fillings such as red bean paste or custard. Hong Kong has always been a point of confluence for international cuisines, thanks to waves of migrants and international travellers that have washed over the city, leaving behind everything from borscht and fluffy cakes to buns inspired by Mexico. Wong notes that, while the buns may use custard, they also bear the mark of a local twist. “The custard is further enriched with salted egg yolks, milk powder, white sugar and evaporated milk,” he says. “This gives our Hong Kong buns a silky and dense texture and rich flavour.”
Credit for that innovation goes to Spring Moon, the Chinese restaurant that opened in the Peninsula Hotel in 1986. Yip Wing-wah, the restaurant’s dim sum supervisor, recalls in a Michelin guide interview that not a lot of hotels had Chinese restaurants at the time; most served Western cuisine. The same had been true for the Peninsula, and in a nod to that heritage, Yip and his chefs decided to add a few Western-inspired elements to their menu. “We began by adding custard to some of our dim sum in place of lotus [paste], creating custard buns in the process,” he recalls. “That ended up being a real hit with diners.”
By the 1990s, creamy egg custard buns had become popular across the city. Auntie Wong, a dim sum cart lady who has been working for Lin Heung for more than a decade—she shyly declined to reveal her full name—says that they were in high demand about 30 years ago. “I find it a delightful treat too – it’s rich and sweet and creamy,” she says. Tse Kin-hoi, who works at Dim Sum Square, a modern dim sum chain, says egg custard buns have become a staple that every dim sum apprentice learns from their master.
The custard filling has lent itself to other treats, too, including custard-layered Malaysian-style sponge cakes and and crystal creamy custard buns. Soon after inventing the egg custard bun, Spring Moon launched a custard-filled mooncake for Mid-Autumn Festival. Decades later, their popularity seems unabated. Every year, customers queue for hours in the Peninsula to get their hands on a box of custard mooncakes. In 2011, after the mooncakes sold out in a day, disappointed custard fanatics occupied the hotel lobby until the Peninsula got them to leave by offering them compensation.
Though custard remains as popular as ever, the buns that launched the craze have become harder to find, thanks to an oozing, hard-to-resist variation on Spring Moon’s invention. Perhaps inspired by lava sesame paste buns that were a common dim sum item until the 1970s, lava custard buns are made with a higher proportion of salted egg yolks and lard or vegetable oil, which prevents the custard from fully setting, giving it an unctuous texture. The lava buns are more savoury and less sweet than the creamy custard buns, which Wong says is appealing to Hongkongers concerned about their sugar intake. “In our Chinese buns, we have reduced the amount of sugar by one third,” he says.
In the age of social media, the buns have another point of appeal, too: their oozing centre is perfect for Instagram videos. One restaurant even produces emoji-themed lava buns, with the yolky custard spilling out of the cartoon character’s mouth.
Today, the original egg custard buns are found mainly in traditional tea houses. Wong says that, at Lin Heung, only a few bamboo baskets of buns are sold during weekdays, and a little more than 10 on weekends. This stands in contrast to lotus seed paste and char siu buns, both of which sell around 40 to 50 baskets per day. But Wong is committed to keeping the old-style buns on the menu. “We’re an old tea house,” he says. “Mostly we make the buns for some of the remaining old customers, and sometimes tourists, who like the recipe the original way.”
Interestingly, while the original buns are disappearing in Hong Kong, they have found a new home in mainland China, where they are a popular order in big Guangzhou restaurants such as Tao Tao Ju, Nan Yuan and Guangzhou Restaurant. Wong points out that many of these restaurants hired their dim sum chefs from Hong Kong and they brought some of their favourite dishes with them.
“The original creamy egg custard bun may disappear in Hong Kong, but I’m sure it will continue to exist in a lot of variants,” says Terence Lam, who runs public relations for Lin Heung. Even if the bun itself fades from menus, its legacy survives in mooncakes and in the lava buns that remain a hit. It’s a typical Hong Kong story, where cultures, ideas and histories are baked—or rather, steamed—together.
Where to find egg custard buns
1/ Lin Heung Tea House (closed in August 2022)
162 Wellington Street, Sheung Wan. Tel. 2544 4556. Open every day, 6:00 – 22:00.
2/ Choi Lung Restaurant
2 Chuen Lung Estate, Route Twisk, Tsuen Wan. Tel. 2490 4711. Open every day, 6:00 – 15:00.
3/ One Dim Sum
G/F 209A-209B Tung Choi Street Prince Edward, Mong Kok. Tel. 2789 2280. Open Monday – Friday, 10:00 – 24:00; Saturday and Sunday, 9:00 – 24:00.
This article makes use of the jyutping system of Cantonese romanisation.