JUDY Mertens does not subscribe to the Western notion that children should be seen and not heard. Her son was indirectly responsible for her first entrepreneurial venture - a mail-order cookie company - and directly responsible for the second: a takeawaycoffee business, Coffee Central, to open in Alexandra House later this month, subject to licence approval. The cookie concern, A Very Special Delivery, began in 1989 soon after Zach Mertens went off to school in the United States. What he missed most, he told mum, was her cookies. Sending them from Hong Kong was impractical, so Mrs Mertens arranged for an American friend to bake and despatch them on her behalf. Hong Kong soon heard of the service, and people with relations and friends in the US began placing orders. Realising the size of the market, Mrs Mertens left her job and the cookie-baking colleague became a partner. By 1991, between 25 and 30 dozen cookies and brownies were being posted out for Hong Kong clients each week. Then Mrs Mertens' husband received a posting to India, and the business naturally crumbled. When the position failed to materialise, Zach - by now a graduate - came to his mother's rescue. ''Having been impressed by the widespread availability of good coffee in America's Pacific northwest, where he was studying, Zach suggested a similar concept would go down well in Hong Kong,'' Mrs Mertens said. A takeaway shop was the original plan. But after months of searching for suitable premises in Central, and finding everything too expensive, a coffee cart was deemed more suitable. By this time, Zach had taken a job back in the US and Mrs Mertens persevered alone. ''I sent out business proposals to eight major leasing agents,'' she said. ''Then finally, after a year, Hong Kong Land expressed interest.'' One only needs add up the number of American-style coffee outlets that have opened in the past year in Hong Kong - the Pacific Coffee Company in Admiralty, Uncle Russ's Coffee in Kowloon, The Bagelria in Central, and Cappuccino in Causeway Bay - to realise demand for speciality coffees is growing by the day. Hong Kong Land, Mrs Mertens said, recognised the time was right, liked the novelty and convenience offered by a cart, and agreed to a location at the Chater Road entrance lobby of Alexandra House. ''They feel it will give their tenants a good start to the day,'' she said. Dark blue and coffee cream-coloured, the cart measures four metres. Made to order in the US at a cost of US$11,000 (HK$85,000), a number of modifications had to be incorporated to meet stringent local licensing requirements - a double sink, for example. ''Now all you need to do is plug it into the electricity supply,'' Mrs Mertens said. ''It's totally self-contained.'' The cart features an amazing amount of equipment for such a small space. Along with the espresso machine, fridge, percolator, grinders and cash till, there is a granita machine for iced coffees and slush-type fruit drinks. In addition, there will be a fax machine for advance multiple orders - a boon for long meetings in need of a shock-awakening. So much for the trappings. What about the all-important coffee? Hong Kong tastes may have come a long way in the past year or two, but Mrs Mertens still feels one blend is enough for now. ''We've chosen Espresso European which we're importing from Portland, Oregon,'' she said. ''I don't think tastes are discerning enough yet to distinguish between different blends. ''I think people need to learn gently. Perhaps we'll expand later on.'' The drinks on offer, in 225 ml and 335 ml sizes, will include regular and decaffeinated brewed coffee, cappuccino, espresso, latte and mocha, as well as the granita flavours. Prices range from $14 to $16. To catch the breakfast and snack trade, there will also be brownies - made to the A Very Special Delivery recipe - and muffins. The emphasis, however, is firmly on quickly-served, quality coffees. Four uniformed staff will man the cart at all times to ensure high turnover. ''We don't want to make anyone wait,'' Mrs Mertens said. ''My goal is to provide quick, pleasant service, which I think will count for a lot.'' For optimum efficiency and authenticity, a coffee cart consultant will be brought in from Portland to oversee the first 10 days of business. ''I think it's going to be a lot of fun,'' Mrs Mertens said. ''I'm looking forward to serving people with a smile and giving them a break from daily routine.'' Coffee Central: G/F Alexandra House, Central. Planned operating hours: Monday-Friday 7.30 am-6.30 pm; Saturday 7.30 am-2 pm; closed Sunday.