Spicy Pork with Fresh Mushrooms and Chinese Olives

One of the great treats available in the Hong Kong markets is fresh straw mushrooms; they were originally cultivated on rice straw, hence the name. They are like button mushrooms in the West but have a more subtle and delicate, earthy flavour. Because they are difficult to store and deteriorate rapidly, they are not exported. Although they are available in tins in the West, I prefer to use them fresh. Olives are believed to have been first planted in China during the sixth century AD but ar