Vietnamese caramel trout

Name: Vietnamese caramel trout
Prep time: 5 min
Cook time: 15 min
Total time: 20 min
Cuisine: Vietnamese
Ingredients: 50g golden caster sugar; 1 tbsp Thai fish sauce; 1 red chilli , finely sliced; large piece of ginger , finely sliced; 2 rainbow trout fillets; 2 heads bok choi , halved; juice ½ lemon; coriander sprigs; steamed rice , to serve