Chop the shallots, ginger and garlic.
Heat the groundnut oil in a wok and stir-fry the shallot, garlic and ginger for 2-3 minutes.
Add the chilli flakes, stir, then add the vinegar, soy sauce and let it bubble for a minute or so. Turn off the heat and add the sesame oil.
Put a bamboo basket or a metal steamer in a wok filled with a little water. Make sure the water doesn’t touch the base of the steamer or basket.
Line the basket or steamer with a large piece of parchment paper and put the fish in the basket ( you could use a plate instead). Spoon some of the sauce in the cavity of the fish and pour the remaining over the top. Wrap with the paper.
Put a lid on. Turn the heat on and bring to the boil. Steam for about 12-15 minutes until the fish flakes easily.
Serve warm.