Combine Group 1 ingredients in a dry, heatproof bowl. Set a fine sieve over another empty bowl.
Heat oil and all Group 2 ingredients in a pan on low heat. Watch closely — turn off the heat as soon as the spring onions turn brown.
Pour the hot oil through the sieve into your empty bowl.
Add half of the chili mixture — it should bubble intensely — then add the rest once it calms. Stir well.
Let cool, then store in a clean, airtight jar in the fridge for up to 6 months. Wait 12 hours before using to let the flavors develop.
