Edamame are young soy beans boiled with salt, and they are eaten hot or cold. You may well have come across them in Japanese restaurants, where they're served as a snack. Specialist Japanese food shops and some supermarkets stock them. British-grown edamame will be available for the first time this summer. This dish makes a refreshing light meal, though you can turn it into something more substantial by adding fried tofu and/or roasted peanuts. Serves four.