WHEN an organic farm-owning environmentalist tells you where the best vegetarian restaurant is, you listen. I met Simon Chau Sui-cheong informally, and formally complained that most vegetarian restaurants in Hong Kong had a sameness to cooking, ingredients and - most of all - the insidious peanut oil for every recipe. He looked scornfully at me (greenies can be more disdainful about carnivores than immigration officials are about illegals), and said three words: ''Kung Tak Lam.'' Actually Mr Chau was not being scornful at all. But after many years of eating raw hay, autumn leaves and tree sap, I imagine one's mouth inevitably takes on an earthward appearance. ''Kung Tak Lam is not your ordinary vegetarian restaurant. It's Shanghainese. They use a special oil for cooking. It's run and created by Lau Wo-ching, a magical man in vegetarian food. They even fry the hair off corn cobs,'' Mr Chau said. Well, the very thought of fried corn-hair was juicy enough to get six of us visiting the restaurant one Saturday evening. Where, for instance, can you get lightly fried rice mixed with seaweed and crunchy pine-nuts? And talking of crunchiness, you can open with crunchy whole bean sprouts with a hot Sichuan sauce. Beancurd? Forget the usual bland concoctions and try the fried beancurd rolls which came with fresh tung koo mushrooms and angled luffa. It was firm, tasty and made a great contrast with the other dishes. There was nothing special about the stewed eggplant, which tasted like . . . well, stewed eggplant. On the other hand, the ''Fried Grass-Stem Shreds'' had that healthy green-and-white tastiness which only grass can offer. Yes, we did not smoke it. Even the most ordinary cold dish, mashed beans with vegetables, had a lightness to it which virtually levitated our group. What is the secret of this most magical restaurant? The 65-year-old Lau Wo-ching is not loath to admit one secret: the cooking oil. ''Some of the dishes are cooked in peanut oil,'' he confessed. ''But the lightest dishes are cooked in an oil we make ourselves, from the camellia flower. The flower itself is used mainly for cosmetics, but up in the mountains of central China, they use it for cooking. I decided that this would be better than the usual peanut oil for certain delicate dishes.'' Originally a Shanghai film-producer, Mr Lau turned to vegetarian cooking 20 years ago when doctors told him he was too stout. Taking to the cuisine with a passion, he studied with his ''master'', Sam King Chee. Later, he went on his own, blending herbs, vegetables and mushrooms for a particularly light cuisine. Three years ago, he opened his five-table restaurant in Causeway Bay, near St Paul's Hospital. Last year, with business thriving, he opened a much larger place in Kowloon. Mr Lau's imagination, though, does not depend on size. For a simple opening peanut dish, he adds seaweed to the salt. For another cold dish, he mashes raw soya beans, mixes in some preserved mustard roots from Beijing, and lightly sautees the mixture, which is a little sweet, a little crunchy. The fried corn-hair was not available last week, but a lot of grass-stem noodles were in town. ''We bring the grass in especially from Hangzhou,'' he said. ''Then we blend the grass with regular wheat noodles from the market. The result is especially healthy, especially when cooked with camellia oil.'' Mr Lau is also a mushroom fanatic. What he calls top-grade mushrooms on his menu are actually rare hedgehog mushrooms from Manchuria. Everything is done with care. When we had fried rice with bits of seaweed and pine-nuts, nobody could believe that it was fried. Each grain stood out, without any grease or browning taste. ''This is not easy,'' Mr Lau said. First, we have fresh seaweed. Then pine-nuts for a bit of snap. The rice is the important thing. I can't stand greasy food, so we pour the absolute minimum of oil into the wok for the rice. Then the secret is to keep the rice moving, moving, moving around, so none of it sticks to the bottom. It isn't easy, but the taste is worth it.'' Perhaps one reason is that when he opened the restaurant, he decided to sell beer - an absolute taboo in Cantonese vegetarian restaurants. Not only that, but Mr Lau encourages diners to bring their own wine, European or Chinese. ''Why not?'' he asks. ''This isn't a hospital. This isn't a temple. It happens to be a restaurant. We want people to enjoy themselves.'' Kung Tak Lam Shanghai Vegetarian Restaurants: 15 Hanoi Road, Tsim Sha Tsui. Tel: 367-7881; 35 Tunglowan Road Causeway Bay. Tel: 890-3127.
