Quarter the cabbage, remove the stalks before chopping it into 4 cm pieces. Place in a bowl and sprinkle with salt, massaging it into the leaves
Cover the cabbage in filtered cold water, sit a plate on top to keep submerged and leave overnight (minimum of 12 hours)
Rinse the cabbage thoroughly under cold water, before leaving to drain in a colander for 30 mins
Meanwhile, mix the garlic, ginger, red pepper flakes, sugar, fish sauce and salted shrimp into a paste
Add the spring onions, daikon (or carrots), and dried cabbage in a large bowl and mix in the spice mix, using your hands (you may need to use gloves)
Transfer the cabbage mixture to a large airtight container, pressing it down so it is covered by its own juices, and leaves a gap at the top, before sealing
Leave the container out in room temperature for 3-5 days (depending on your taste preference), opening and letting out some gas daily and pressing down the vegetables in the liquid. Once the taste has developed, store in an airtight container in the fridge for up to 4 weeks (or longer – remember it will continue to develop it’s taste and smell!).