When simmering the stock in step 4, top up with water if it looks like it’s reducing too quickly.
By the end of the stock cooking time (step 5), the stock should have a rich, deep flavour. Taste, then leave to cook a little longer if it doesn’t.
Use a metal spoon or ladle to skim the stock (step 4), sweeping it over the surface gently to remove excess fat and scum. Put the melted fat in a bowl and chill until solid before discarding.
Don’t skip the charring stage for the onion and ginger (step 3); it imparts a sweetness and extra depth of flavour to the broth.
You can carry out steps 1-5 in advance, then shred the chicken, cool and chill overnight, or for up to 48 hrs. When ready to eat, reheat the stock and chicken gently until simmering, then serve as per steps 6 and 7.