"The importance of social media in China cannot be overstated. For example, we launched a limited-time offer item last year, the molten cheese fondue slider, which attracted a lot of attention due to images of it being shared on platforms like Douyin. The highly digitized social lives of our customers impact how we approach things.

"Another major lesson we learned here is the disruptive power of delivery platforms. Our products, and burgers in general, seem like an ideal fit for delivery. People who are pressed for time or eating alone can have our burgers delivered to them in 20 or so minutes."

The Californian burger chain The Habit Burger Grill has also enjoyed brisk business in Shanghai. Since opening its first burger joint in Nov 2017, the brand has expanded to three other locations in the city. Candice Tao, one of the branch managers, says the company aims to have 25 outlets in Shanghai by 2023, five due to be open this year.

Industry experts have offered various reasons as to why burger chains are flocking to the Chinese market. Chef-turned-food-writer Christopher St. Cavish says consumers in the city have always been enthusiastic about new offerings.