Place the oil and spring onions in a medium pot over a medium heat. Cook for 5-15 minutes until the spring onion greens and golden brown and crispy. Assess the heat, turning it down if need be. Continue to cook until the spring onions are a deep brown (but not burnt!) and shrivelled. If you take a few out of the oil (and allow to cool before touching) they should feel super crispy. This is as important for taste as it is for food safety, so don’t rush this step (see notes).
The spring onion greens will crisp up further when they are removed from the oil. Once they are browned and crisped to your liking, scoop them out of the oil with a slotted spoon and place onto some paper towel. Set aside.
Turn the heat to low medium. Add the ingredients for the infused oil to the pot. Continue to cook for 5-10 minutes or until your oil is super aromatic.
Combine the ingredients for the crisp in a medium/large heatproof bowl.
Once the infused oil is fully infused, pour it over the crisp ingredients in the heatproof bowl. The mixture should sizzle and the chilli should bloom to be a bright red colour (this is why a bright red chilli like Korean/gochugaru or Kashmiri is important).
Add the crispy spring onions back into the mix and stir to combine. Allow to cool slightly before adding the finishing ingredients to your tastes.
Make sure you cool the oil quickly and transfer to a sterilised jar in the fridge.
Consume within 4-10 days and freeze the remainder in small batches to be defrosted at your leisure.