Wing beans are the seed pod of a decorative vine Psophocarpus tetragonolobus, which is native to Southeast Asia.
The unkempt vine will trail over fences and dwellings in the appropriate climate and bears attractive flowers. Depending on the hybrid, these will range from white through to vivid blue.
The bean itself grows to a length of about 10 centimetres (4 inches) and has a strikingly original appearance. Instead of a regular long and slender bean, these leguminous marvels are block shaped, with 4 distinctive and frilly wings protruding from each edge. The rectangular central core contains tiny black, edible seeds. The bean itself is almost always green, but there are some oddball varieties, which present themselves as pink, purple or red.
In cookery, wing beans will often be found in stir fried dishes, where their distinctive appearance and tantalizingly crisp texture is much appreciated. Thai cooks often use wing beans in salads, or briefly boiled and served with a deliciously pungent dressing known as nam prik.
This sensational vegetable, as with many Asian greens, goes by many common names, so for the sake of identification, look for; asparagus beans, four angled beans, frilly beans, manilla beans, Goa beans and princess pea. Ethnic names include the Chinese su-ling dou, Malaysian kacang botor, Japanese shikakumame and the Thai thua pu.
Try adding wing beans to your next stir fry, or perhaps the following Thai dish, simply served with nam prik, or Thai relish. It is a treat on a summer day with a crisp, cold beer.
Wing beans with nam prik
300 gm (2/3 lb) wing beans, sliced into 3 if large
3 Tbs dried Asian shrimp
1 clove garlic, peeled and chopped
2 shallots, peeled and chopped
3 hot red chillies (red peppers), chopped
60 ml (2 Tbs) lime juice
60 ml fish sauce
60 ml water
3 Tbs palm sugar
Soak the dried shrimp for 30 minutes in some hot water. Drain away the liquid. Combine the shrimp, garlic, shallots and chillies in a mortar and pestle. Grind until you have a coarse paste. Alternatively, this step can be done in a food processor, but remove the seeds from the chillies as the pulverizing action releases more capsaicin, which means a hotter sauce. (The seeds contain most of the heat, along with the white membranes)
Tip the paste into a bowl and combine with the remaining ingredients. Allow the nam prik to sit for half an hour to let the flavours assimilate.
Boil the wing beans in plenty of salted boiling water for 5 minutes, drain, then immediately plunge into cold water to stop the cooking and set the vivid green colour. Pile onto a platter and serve with the nam prik on the side as a dipping sauce.