Kang says the clay pot makes the soup rich. As clay pots are easily broken, Kang asks his ch-1efs to handle the old clay pots with special care.

According to Kang, 70 percent of the ingredients he uses at his restaurant are from Shaanxi. Tofu from Liangjiahe village is just one example, as it's flown in from Yan'an to the capital each day.

"To assess the taste of tofu, you have to check the quality of the soybeans and the water-these are the only two things you need to make tofu," says Kang. "And the quality of both the soybeans and water are checked in Liangjiahe."

Roujiamo, or Chinese hamburger, is also a traditional dish of Shaanxi. The most common version uses a plain pancake, while Kang chooses the style of his hometown, Tongguan county in Weinan, which uses lard to create a crispy, multilayered version.

For the pancake filling, pork from black pigs raised in Shaanxi province is used. "When I was a kid, every family raised this kind of black pig, which is small and grows slowly, and the meat tastes delicious," says Kang.

"But, as I grew up, a new kind of pink pig which grows much faster and bigger suddenly replaced the black ones. However, they are not as tasty," he says.

Kang finally found a place that still raises the traditional black pigs, and he decided to use their meat to make the roujiamo, which reminds him of the taste of his childhood.

Roujiamo is always served with rice noodles. Unlike the usual chili oil sauce, at Chang An'G, Kang prepares rice noodles in tomato sauce which also comes from his childhood memories. Peeled tomatoes are fermented in a can with salt and ginger for days before they're chopped and fried with chilis.

"It's a traditional sauce in my hometown, which I want to pass on," says Kang, adding that Beijing diners prefer to eat rice noodles with sesame sauce, which is not common in Shaanxi.

Rice spirit is another Shaanxi specialty. Kang has selected several types of local varieties. One highlight is a spirit that uses black rice, black sesame, black beans, black dates and walnuts to create a dark and nutritious tipple.

"We know that people in old Chang'an would drink a lot without getting drunk, because the truth is the rice spirit has an alcohol by volume content of just 2 percent," says Kang.