The yuzu is an odd citrus fruit. When fresh, it isn't pretty - it looks dry and shrivelled compared with plump, heavy and glossy skinned oranges, lemons and limes. When you cut a yuzu open, it seems almost entirely filled with seeds and is not juicy. Still, it's a popular fruit because of its distinctive, delicate and delicious taste.
The fruit is used primarily for its aromatic zest and thick skin. It's difficult to find fresh yuzu in markets but you could try Japanese shops, such as Apita in Taikoo Shing and Fresh Market in the basement of Sogo in Causeway Bay, although their supply is inconsistent. Fortunately, yuzu-flavoured products are easy to find. Koreans make a thick yuzu marmalade that's sold at many supermarkets; it makes a delicious, soothing drink when stirred into hot water. You'll also find yuzu sake, non-alcoholic drinks and confectionary imported from Japan. Yuzu is also frequently used as an ingredient in ponzu, a tart, vinegar-based sauce served with fish and meat.
Japanese chefs often use just the zest and discard the rest of the fruit but most of us try to use the entire yuzu if we manage to find it.
I was given two yuzu a couple of years ago and wanted to make the most of them. Two aren't enough to make marmalade, so I cut the fruit into quarters, leaving it intact at the base. I put the yuzu in a tall glass jar and poured in enough good-quality unflavoured vodka to cover the fruit. I let the ingredients infuse in the fridge for a few months before serving the vodka, which has a pale yellow tint. Every time I take from the jar, I add more alcohol and, surprisingly, the fruit still has flavour, although it's getting weaker.