Pour the stock into a large casserole dish and put on a medium heat – bring to a simmer.

Chop the shallots, ginger, spring onions and chilli. Add to the stock. Bruise the lemongrass with the back of a knife and add that too.

Add the fish sauce, soy sauce, chopped mushrooms, chopped pak choi and chopped coriander stalks.

Place the fish gently, skin down, into the stock. Simmer for about 5 minutes, depending on how thick your fish is, until cooked all the way through.

Chop the coriander leaves and scatter over the top for the last 30 seconds of cooking.

To serve, place a large spoonful of rice in the middle of a bowl, top with the fish and then ladle over as much of the delicious stock as you can.