Pickled ginger is made from young ginger, which is usually available from mid-spring to mid-summer. With its pink or green tips, thin, pale skin and moist, mild flesh, this ginger – also called spring ginger – is very different in looks and flavour from the hard, tan rhizomes with a fiery taste that you can buy year-round.
Most people are familiar with young ginger in pickled form, which is served with sushi because it helps to clear the palate between bites of some of the fattier, more strongly flavoured types of fish. You can find it in the Chinese and Japanese section of supermarkets, and if possible, buy the type that's in small chunks, rather than thin slices.
Buy a small chicken that's about 1.2kg (42oz), and have the butcher cut it up Chinese-style, through the bones into bite-size chunks.
Put the chicken pieces into a bowl. Add the soy sauce, rice wine, salt, sugar, cornstarch and sesame oil. Stir well to combine then leave at room temperature for an hour, stirring occasionally.
If the ginger is in chunks, cut it into 1cm (⅜in) pieces.
Pour cooking oil to the depth of about 7.5cm (3in) into a medium-size pot. Heat over a medium flame until the oil reaches 180°C (350°F). Leaving behind as much marinade as possible, fry chicken in several batches. Fry the pieces just long enough to sear the exterior but not cook the meat, about one minute, stirring frequently. Drain the chicken on paper towels. Keep the marinade in the bowl.
Put the chicken into a large clay pot. Pour 120ml (½ cup) of water into the marinade in the bowl, stir well, then pour this over the chicken, then mix in the ginger pieces. Place the pot over a medium flame, cover with the lid and bring to the boil. Lower the flame and simmer for 30 minutes, or until the chicken is cooked.
Slice the banana chillies on the diagonal about 3mm (⅛in) thick, and the spring onions into 3cm (1¼in) lengths. Stir the chillies and spring onion into the pot and cook for another five minutes.
Taste the sauce and correct the seasonings, if necessary.. Check the consistency of the sauce – it should lightly coat the chicken pieces. If it's too thin, dissolve a little additional cornstarch in some water and pour this into the simmering liquid. Cook until the sauce thickens sufficiently, stirring occasionally.
Serve immediately with steamed rice.