2ounces(50 grams) Sichuanese or Korean ground chilies
Small piece of gingerunpeeled, crushed
Heat the oil over a high flame to about 400°F, then leave for 10 minutes to cool to around 275°F.
Place the ground chilies, sesame seeds and ginger in a heatproof bowl. Have a little cool oil on hand, just in case. When the oil has cooled to the right temperature, pour a little onto the chilies; it should fizz gently but energetically and release a rich, roasty aroma. Pour over the rest of the oil and stir.
If you think the oil is too hot and the chilies are likely to burn, simply add a little cool oil to release the excess heat. Do, though, make sure that the oil is hot enough; without the fizzing, it won’t generate the rich, roasty fragrance you need.
When the oil has cooled completely, decant it and the chili sediment into a jar and store in a dark, cool place. Leave it to settle for at least a day before using. The chili oil will keep indefinitely.