Down a narrow, stone-paved alley a few minutes' walk from Kathmandu's bustling tourist hub of Durbar Square, Uttam Manandhar prepares a tapas-style array of buffalo brain, spine and testicles.

It might not look appetising to Westerners but dozens of indigenous Newars gather daily in his "bhatti" as part of a centuries-old social scene largely missed by the thousands of tourists who come to Nepal in search of culture.

Hidden in the capital's myriad labyrinthine alleyways are hundreds of these traditional hole-in-the-wall eateries -- "speakeasies" to the locals -- serving potent home brew and various buffalo meat snacks.

"These are the daily staple of Newars. I think the locals come here because, apart from being cheap, they are also nutritious and delicious," Manandhar said, multi-tasking between a boiling pot of spinal cord and some fried intestines.

Both sides of the alley are dotted with these grimy, smoky coves which can be identified by those in the know by the greasy green curtain covering their doorways.

Inside, a dozen Newari dishes comprising beaten rice and every conceivable part of a buffalo, are spread out before the hungry locals, who wash down their spicy barbecued, or sometimes raw, meat with a rice-gin concoction called raksi.

Locals part with around 100 rupees ($1.83) for a filling meal while a double shot of home-distilled raksi -- so potent at more than 50 percent alcohol that you soon forget how many you've had -- costs little more than 40 rupees.

The delicacies on offer include buffalo brain, a greyish dish of boiled blood called rakti, phokso (lungs stuffed with minced meat), kachila (raw meat), baked buffalo skin, boiled spinal cord and fried intestines.

But the tourists who throng the courtyards of the nearby 17th century temples and other attractions in search of the "genuine" Kathmandu experience hardly ever venture here, says Manandhar.

"These places might be dark and not polished if you compare them with the fine dining places in Kathmandu. But once your palette knows about it, it will be hard for you not to be tempted by them," he told AFP.

A typical bhatti might serve 60 people on a good day, making around 4,000 rupees after expenses are deducted, although staff costs are low, with the owner usually doubling as waiter, barman and chef.

"We are busy in the late afternoon and the evening when our customers, mainly local Newar people, come to eat and socialise," Manadhar said.

Sitting under a naked bulb in a long room with wooden chairs and tables, Narendra Gopal Shrestha is enjoying a plate of potato stew and soya bean and cucumber pickle with a generous helping of chilli and vinegar.

"I grew up eating the Newari food at home and I can't think of a day when I don't have it. It's found nowhere else except Kathmandu and it's cheap and the best," the 53-year-old tour guide told AFP.

"My kids go out to expensive restaurants where they serve junk food like pizza and burgers. I think it's only the older generation that knows the value of this cuisine," he said.

Shrestha said the food reflected a rich culture that drew from his people's unique mix of Buddhism and Hinduism and their agrarian past, when they supplied the food to their farm-hands.

Diners in Kathmandu's bhattis are united about the quality of the food, but it's the raksi or tongba, a rice beer sipped through a pipe, that really stirs their passions during the capital's chilly winters.

Because bhattis are hard to find, they have never been counted. And although there were several bhattis in every alley ten years ago, their numbers are diminishing, according to food experts.

"These places emerged before fast food and the arrival of dining out culture. Back in the 1970s, creative people used to hang out there and spend hours over plates of the snacks and drinks on the side," said food writer Shekhar Kharel.

Kharel believes diners have become more knowledgeable and cosmopolitan as Kathmandu has opened up to the world in recent decades, gradually rendering restaurants serving only one type of cuisine obsolete.

"Bhattis are now the poor cousins of the neighbourhood's upscale cafes," he said, adding that it was not all bad news.

"Although they are threatened by the newcomers, there are some who enjoy a loyal following. They might retain their glory if they modernise a bit because you won't get the authentic taste anywhere else."