Soy-braised chicken thighs with star anise recipe

This is adapted from an excellent American book, 'All About Braising' by Molly Stevens (WW Norton, £25). It has quickly became one of the most cooked dishes in my house as it's easy and the children love it. Don't be tempted to add more star anise – one is enough.
2½ tbsp groundnut oil
8 chicken thighs
2 tbsp soy sauce
2 tbsp rice vinegar
2 tbsp fish sauce
2 tbsp soft dark-brown sugar
1 red chilli, halved, deseeded and finely shredded
2.5cm (1in) piece root ginger, peeled and very finely chopped
3 cloves garlic, very finely chopped
1 bunch spring onions, trimmed and cut on the diagonal
3 strips orange rind
1 star anise
50ml (2fl oz) water or chicken stock
2 tbsp orange juice
2 tsp cornflour (optional)
Heat 1½ tbsp of the oil in a sauté pan or casserole (something in which all the thighs can lie in a single layer). Brown the chicken on both sides. Don't try to turn them until they are easy to move; pulling is an indication that the meat isn't brown enough and will tear the skin. Set the thighs aside and pour the fat out of the pan.
Stir together the soy, vinegar, fish sauce and sugar. Heat the rest of the oil in the pan and add the chilli, ginger and garlic. Set aside the greener bits of spring onion and add the rest to the pan. Cook over a medium heat for a couple of minutes, until the garlic is golden, then add the soy mixture. Put the chicken back in the pan, skin-side down, along with any juices, plus the orange rind, star anise, water or stock and orange juice. Grind on some pepper.
Cover the pan and put in an oven preheated to 180°C/350°F/gas mark 4 for 40 minutes. After 15 minutes turn the chicken over and return to the oven. Remove the lid for the final five to 10 minutes. You can either serve the chicken as it is with its thin soy juices, or thicken them with cornflour. To thicken, stir the cornflour in a cup with 2 tbsp water until smooth. Put the chicken in a warm serving dish and add the cornflour to the pan. Heat, stirring, until the juices thicken a little, then pour over the chicken. Scatter with the reserved spring onions and serve with boiled rice and a watercress salad or stir-fried cabbage or pak choi.