It is hard to find another food that is so deeply loved by Shanghai natives, those from elsewhere in China as well as people abroad, than xiaolongbao, or small steamed buns.

The buns, featuring a pork filling, thin wrapping and succulent soup, are served hot with vinegar and ginger after being freshly steamed.

The buns are made with simple ingredients – flour and pork, but have a profound history and represent integrated cultures, just like the city of Shanghai.

The buns have become a popular topic among overseas viewers on TikTok with nearly 200 million views in 2021.

The buns are an icon of Haipai, or the Shanghai-style culture, blending the tradition and fashion of Shanghai. Even the city's official WeChat account, Shanghaifabu, features the buns as the image of its mascot.

Numerous illustrious celebrities have become fans of the Shanghai steamed buns over the years, including Hollywood legend Charlie Chaplin and British philosopher Bertrand Russell. The traditional snacks were also served to foreign dignitaries such as Queen Elizabeth II and former US president Bill Clinton.

Popular blogger Martina Sazunic and Simon Stawski from Canada said "whoever made this, whoever found that idea, deserves like a Nobel Peace Prize in food" after tasting the steamed buns.

Chef Christopher Cavish from Miami wrote a guidance of Shanghai small steamed buns for local diners after tasting 52 local restaurants in a year and a half.

"Fuchun small steamed buns taste like a marriage lasting for half a century, slovenly but still in love," Cavish writes in the guidance.

In fact, the small steamed buns did not originate in Shanghai. Their birthplace is said to be Changzhou, in neighboring Zhejiang Province, in mid-1800s.

Shanghai has various schools for making the buns, including those from Suzhou, Nanjing and Wuxi in neighboring Jiangsu Province, and has developed its own characteristics and world-famous brand.

Nanxiang is the synonym of Shanghai small steamed buns. The brand was founded in 1871 by restaurant owner Huang Mingxuan in Nanxiang Town in the outskirt Jiading District.

To stand out from fierce competition, Huang made the wrapping of his buns thinner, added more pork and shrunk the size to avoid being copied by peers.

It gained wide popularity in 1900 when Wu Xiangsheng, Huang's apprentice and distant relative, moved the restaurant to near the downtown Yuyuan Garden during the unrest of the late Qing Dynasty (1644-1911).

Wu further reduced the size of the steam buns so they could be easily delivered throughout the old downtown. Chefs add seasonal treats such as crab meat, shrimp or bamboo shoots.

Customers usually ordered a pot of tea at the Mid-Lake Pavilion teahouse near the Zigzag Bridge and asked Wu to deliver the freshly made small steam buns in bamboo cages.

"A cup of tea and a small steam bun became one of the most classic leisure lifestyles in the city's old town by then," said Shen Jialu, a famous Shanghai food critic.

Nowadays, the original eatery in Jiading's Guyi Garden and the downtown restaurant at the Yuyuan Garden Malls remain the two main schools of the Nanxiang steamed buns. Both parties have claimed to be the most authentic.

Even locals can hardly tell the difference between their flavors, but the making skills are distinctive.

Li Jiangang, a sixth generation inheritor of the skills of small steamed buns of the Jiading Nanxiang restaurant, said an authentic Nanxiang bun must have 16 grams of pork and 18 drapes.

"The pastry wrapping must be made with hands rather than a rolling pin," said Li, 60. He studied the skills from the last generation master Feng Rongquan when he was only 17 years old.

He cooks the pork skin with chicken soup for hours and wraps the jelly with the pork leg meat to create the abundant soup. The fat on the skin must be removed completely to ensure the soup is clear and tasty.

You Yumin, 43, the sixth generation inheritor of Yuyuan's Nanxiang restaurant, has developed her own techniques.

You uses two short wooden sticks to roll dough into a piece of thinner wrapping. She then quickly fills with pork and wraps the buns with 16 drapes.

With her innovation, each steamed bun can now have 20 grams of fillings. This also allows the chefs to create more flavors with fillings such as sea cucumber, crayfish, shepherd's purse and songrong, or matsutake mushroom.

Despite the COVID-19 pandemic, customers still have to wait for about half an hour in a long queue in front of the Nanxiang Steamed Buns Restaurant at the Yuyuan Garden Malls. More than a dozen chain stores have been opened abroad such as in Japan and Indonesia.

Apart from Nanxiang, many other smaller brands have been opened in Shanghai after 1950s and became even more popular among both locals and tourists.

They include Fuchun, a Yangzhou-style dim sum chain store, initially opened on the historic Yuyuan Road in Jing'an District, Jiajia on Huanghe Road in Huangpu District and Wanshouzhai, formerly a state-own canteen on Shanyin Road in Hongkou District.

Restaurants of Suzhou and Wuxi-style small steamed buns, such as Laoshengxing, which feature red soy sauce soup and sweeter flavor, are also popular among many Shanghai people.

These smaller eateries are the common childhood memory of residents living nearby, though the restaurants normally have a small space, old furniture and are crowded.

Wanshouzhai, for instance, which opened more than 70 years ago opposite the former residence of Lu Xun, known as the forefather of China's modern literature, covers only 20 square meters with several old wooden tables and stools.

Customers have to finish their delicacy as soon as possible, because other diners have already been waiting to take over the table and seats.

However, the restaurant has never lost its popularity among diners. It sells over 10,000 buns every day. Even after it opened a new branch at a nearby mall with better decoration and larger space in 2019, many customers still prefer to squeeze in with strangers in the tiny old store to savor the most authentic Shanghai flavor.