Doubanjiang

Instructions

1. Rinse 100 g of dried split broad beans and soak them in plenty of cold water for 12 hours, until they swell and a fingernail dents them easily. Drain well and rub off any clinging skins.
2. Spread the drained beans in a single layer in a steamer lined with muslin and steam over a hard boil for 30 minutes, until a bean crushes between finger and thumb but still holds its shape. Tip onto a tray and spread out to cool to body temperature; they must be barely warm and only just damp, not wet.
3. Toss the cooled beans with 30 g of plain flour so each is lightly coated, then sprinkle over 1 g of koji starter and mix thoroughly with clean hands. Spread 2 cm deep in a tray, cover loosely with muslin, and hold at 28-30C for 3 days, breaking up the cake and turning it once a day. The beans should end up matted with yellow-green mould and smell sweet and chestnutty. Air-dry the bean koji in a warm draught for a day.
4. While the koji works, stem 200 g of fresh red chillies and chop them coarsely, seeds and all, into 5 mm pieces. Mix with 30 g of the coarse salt in a non-reactive bowl, cover, and leave at room temperature for 3 days, stirring once a day, until the chillies slump into a wet, brick-red mash.