Networking and social media websites such as WOM Guide and OpenRice have helped expand the definition, exposing secret hideaways to a wider audience of foodies.

'Private kitchens started over 10 years ago in people's homes and reached a record high six years ago,' says 28-year-old chef Sean Cheung Yiu-wa of Zone-D Ristorante, a private Italian-style kitchen in Causeway Bay.

'The definition of private kitchens is changing. These days, customers are looking for an alternative, comfortable location to eat great food. We see our venture into private kitchens as a small start which might lead to a bigger restaurant.'

Cheung and business partner Lew Low Siu-wai set up Zone-D just over a year ago as a lower-cost alternative to opening a full restaurant.

'I estimate that opening a private kitchen is about one-tenth the cost of opening a restaurant. The difference between restaurants and private kitchens is the smaller overheads for expenses such as rent and staff. If you have a restaurant, the area of rentable space is larger. We keep things lean with myself and Sean doing most of the work. Costs are affected by things such as opening hours, customer turnover and the quality and quantity of equipment in the kitchen. We were keen to start small and maintain the quality of our service and food.

'Also, food-wise, opening a private kitchen is a dream because we can mix up different cuisines. Compared to a restaurant where chefs have to conform, now I can be my own boss. I don't need to follow menus - instead we can cater to special requests and become excited about them.'

This overriding love of food is also shared by Lo Po-wai, owner and chef of Causeway Bay's Meet Lobo. 'The great thing about private kitchens is that we are able to develop new ideas and change menus regularly at a reasonable price,' he says. 'At a private kitchen, a customer's money goes towards high-end cuisine - not high rent, luxurious surroundings or servers.'

For nearly four years, Lo has been creating tailor-made menus involving both Western and Chinese cuisine. 'There has been a trend for private kitchens to mirror the look of five-star restaurants, but it's a slow process. Really, it's all about the food and the ability to control quality.'

Chef and owner Andrew Toh of Western eatery Seven Thirty in Tsim Sha Tsui says success boils down to the basics. 'In a private kitchen, people who are interested in food can really focus on the produce itself,' he says. 'Often in restaurants, the food is beautiful, like a painting, but does it taste good? Quality control can be enforced at small private kitchens. It's my aim that everything comes out of the kitchen should be perfect.'

For an insight into the longevity of Hong Kong's most successful private kitchens, Da Ping Huo on Hollywood Road is the benchmark. This bastion of Sichuan cuisine is still going strong after 13 years - an achievement owner-chef Wong Siu-king attributes to two factors: her love of cooking and her love for performing, which sees her entertain guests after every meal by singing Chinese opera classics.

'Private kitchens should always exude the standards of fine dining - but, in reality, to run such an establishment you have to find pleasure in such work,' she says.

'Many private kitchens have come and gone. To the newer chefs, I wish them best of luck. They need to have their own ideas and work hard. In life, everyone needs to do things well and it all must come from the heart - that is the only reason to get into this business.'

Our pick of the kitchens

Wan Chai, Causeway Bay, Happy Valley:

Lady King?s Private Kitchen

1/F, 20-22 Tang LungSt, Causeway Bay Tel: 2575 7128 Hours: 6.30pm-12am Style: Thai Don?t miss: prawn sashimi, stir-friedclams

Meet Lobo

4/F, Room B, Tak Fat Building, 50-52 Russell St, Causeway Bay Tel: 6438 3363 Hours: 7-11pm Style: European/Chinese Don?t miss: foie gras, rib eye, seabass

Zone-D Ristorante

Room 16, 4/F, 16 Matheson St, Causeway Bay Tel: 9802 5504 Hours: 6pm-11.30pm Style: Italian Don?t miss: beef carpaccio

S.A.E.

2/F, Mirage Tower, 15 Thomson Road, Wan Chai Tel: 2527 2537 Hours: 6.30pm-11pm Style: Japanese Don?t miss: vegetable stick with crab miso

Lai Jong Catering

Rm 301, Des Voeux Building, 25 Des Voeux Rd West, Central Tel: 9013 0686 Hours: 7pm-11pm Style: Chinese Don?t miss: seasonal banquet dishes

Central:

Sichuan Cuisine Da Ping Huo

L/G Hilltop Plaza, 49 Hollywood Rd, Central Tel: 2559 1317 Hours: 6-11pm Style: Sichuan Don?t miss: mau pau tofu, stewed beef brisket

Palace Kitchen

Flat D, M/F, 63-65 Wong Nai Chung Rd,Happy Valley Tel: 2899 2844 Hours: 7.30pm-12am Style: Chinese Don?t miss: abalone

Tsim Sha Tsui:

French Table

Flat A, 9/F, Wing Lock House, 1-3 Lock Rd, Tsim Sha Tsui Tel: 6372 3242 Hours: 6.30pm?11.30pm Style: French Don?t miss: foie gras, wagyu beef, duck thigh

House Kitchen

Shop 2, 15/F, Hai Phong Mansion, 99-101 Nathan Road, Tsim Sha Tsui Tel: 2301 1728 Hours: 7.30pm-10pm Style: Chinese Don?t miss: lobster, abalone

Seven Thirty

Flat B3, 1/F Block B, Friend House, 6 Carnarvon Road, Tsim Sha Tsui Tel: 2369 3730 Hours: 7pm?11pm Style: Western Don?t miss: lamb rack, wagyu beef