Shaobing opened Feng's eyes, and he began an exploration of pastry, learning how to make other traditional Beijing snacks, some of which have seemingly otherwise disappeared.

In 1990, when Beijing held the Asian Games, Feng was assigned to ship snacks to the athletes' village, during which time he became intrigued by an exquisite-looking snack, a sweet treat that was formed of four delicately fried pastry bubbles.

As soon as he returned to the kitchen, he asked his master to show him how to make the snack, which is called tangpao. Nowadays, you can no longer find it for sale, as it requires a superb level of skill to make.

Most of these doughy delicacies hark back to the Forbidden City, when they were originally prepared for the imperial family. Feng decided to learn how to make them from Cui Baolong, a third-generation successor to the art of Fangshan cooking, which imitates imperial cuisine from the Qing Dynasty (1644-1911).

"Now when I eat snacks in restaurants, I will ask their chefs how they make it," says Feng. "We have lost the precious skills required to make some of them by hand, and they have been replaced by machines.

"Take the yellow-pea cake as an example. Some chefs only take 20 minutes to finish preparing it, but in the traditional way, just washing the peas thoroughly takes 20 minutes."

A traditional bean roll, which would take Feng six hours to make, has to be eaten within half a day.

"The flavor and taste of handmade bean rolls can never be replaced by machines," Feng says.