1 - step 1 Put the sugar in a large shallow pan, along with a small splash of water.

2 - Heat gently, swirling the pan, until the sugar has dissolved.

3 - Increase the heat and bubble the syrup until it turns a dark amber colour.

4 - Add the fish sauce, most of the chilli and ginger, then splash in 1 tbsp water to dilute.

5 - Boil again until syrupy, then add the fish fillets, skin-side down, and the bok choi, cut-side down.