Dragon fruit is the oval spiky, bright pink or yellow fruit of a cactus. Pitaya, as it is properly known, is widely grown in the tropics and is incredibly fragrant though it loses some of its delicacy with shipping.
The flesh is sweet and crunchy with a flavour that's like a cross between a kiwi and a pear and inside there are tiny black seeds dotting juicy pink or white flesh.
Look for bright even coloured skin and fruits that feel fairly firm rather than soft. The skin is not edible so scoop the fruit out and dice into tropical fruit salads or garnish summer cocktails.
It is widely available in UK supermarkets.