They serve as a symbol of Hong Kong's unique history, which has successfully blended Western and Chinese cuisines into its culture and heritage.
Li Po-chu, 78, is now retired after running one of these popular restaurants for years in Mong Kok.
"You can find so many types of food in cha chaan teng," says Li.
"I love drinking milk tea most of all. It tastes smooth and really nice. It has become my habit to order a cup of milk tea every time I go into a cha chaan teng."
Hong Kong's British colonial past ensured the presence of Western influences throughout the territory. In the 1930s, high-class restaurants were introduced to the city, but these were expensive and did not welcome Chinese patrons.
Locals were keen to challenge such discrimination and so opened their own restaurants, known as cha chaan teng, or "tea food halls", serving affordable Western-style food for people from all walks of life. Their popularity increased, and as they began to open up around the city, they became a regular part of Hong Kong culture.
Today their modestly decorated interiors, which often seem to be stuck in 1950s style, are instantly recognisable. They have wall-mounted electric fans, booth-style tables and chairs that seat four or six people together, and menus visible below glass-covered tables.
Sometimes during peak hours, customers will have to share tables with strangers. This practice of sharing tables is known in Cantonese as dap toi.
The varied fare on offer has become some of the most popular in Hong Kong's food culture.
The British habit of drinking black tea with milk and sugar influenced the emergence of the Hong Kong-style milk tea, which substituted hard-to-keep fresh milk with evaporated milk. Yuan yang, a mix of coffee and milk tea, was also introduced. Its literal translation is "mandarin ducks": male and female mandarin ducks are often seen together as a pair, but look very different.
Other popular items on the menu are egg tarts and Sai do si - Hong Kong-style French toast, topped with syrup and butter.
Because of the city's fast-paced lifestyle, the cha chaan teng used abbreviated names and jargon to speed up the ordering. "Jargon is one of the characteristics of cha chaan teng," Li says. "When I was a teenager, I really thought words like yuan yang, han gaai ["walking on the streets", or "takeaway"], juk [which translates literally as "rice king", and is the name for congee] and fei sa zau lai ["Flying sand without milk" for black coffee without sugar] were the real names of things. They sound quite funny now when I think back."
This is the fourth in the six best Heritage Detective series covers, written by Hong Kong students. This week's Heritage Paparazzi team is from St Paul's Secondary School, Happy Valley
Team: Venisa Wai and Joyce Wai (photographers); Winky Choi (writer and photographer); Isabella Lam (writer, editor); Melissa Cheung (leader)