Heat the oil to 200C and add the star anise, black cardamom, cassia and bay leaves.
Then add the spring onion, onion, and ginger and continue to fry until the wet aromatics appear dry and lightly browned.
Remove all the ingredients from the oil with a strainer scoop and remove the oil from the heat.
Allow the oil to cool for about 10 minutes to around 120C, and then add the dried chilli flakes.
Allow the oil to cool completely for about 1 hour, and then transfer the chilli oil to a jar.
The chilli oil will keep at room temperature for years.
