Shanghai may be well-known for being a fast-paced city that never sleeps, but there is one thing that its residents will slow down for－food.

The latest food craze in the city involves a palm-sized bun topped with dried-meat floss and shredded sea sedges, something many Shanghai-nese normally dislike because of its coarseness.

The bun is sold by Master Bao, which was first established in a quiet residential neighborhood in Beijing in 2009. The company opened its first Shanghai outlet in People’s Square in early February.

Today, the line outside the shop can stretch hundreds of meters and customers have waited for several hours during peak times. The snack sells for between 19 and 29 yuan per 500 grams, depending on the type of floss.

Bao Caibin, the store manager of the Shanghai outlet, says that the craze in Shanghai is even bigger than what took place in Beijing and Tianjin. He says the line starts to form as early as 5 am and lasts till midnight. The store is currently limiting each customer to 2 kilograms of bread.

It remains a mystery to most foodies why the snack has become such a phenomenal hit because there is nothing new or innovative about Master Bao’s buns. Similar products have been sold at most bakeries across the city for many years.

Most of the customers who were waiting in the line said they were simply influenced by social media posts.

Taobao showed that more than 10,000 such deals for the buns were made over the past 30 days. A shop assistant says that nearly one-third of the orders are placed by customers in Shanghai.