Napa Cabbage Kimchi

Steps

1. 1
   Quarter the cabbage lengthways through the root. Sprinkle the salt between the leaves, more of it on the thick white stems near the root, and leave the quarters cut side up for 2 hours, turning them every 30 minutes, until the stems bend without snapping.
2. 2
   Rinse the quarters three times in cold water to wash off the excess salt and drain them cut side down for 30 minutes. Taste a leaf: it should be pleasantly salty, not briny.
3. 3
   Meanwhile whisk the rice flour into the water in a small pan and cook over medium heat, stirring, for 3–4 minutes until it thickens to a thin glue. Stir in the sugar and let it cool. This porridge feeds the fermentation and helps the paste cling to the leaves.
4. 4
   Mix the cooled porridge with the chilli flakes, fish sauce, garlic and ginger into a paste, then fold in the radish and spring onions.
5. 5
   Wearing gloves, spread the paste between every leaf of each quarter, working from the outer leaves in. Fold each quarter in half and pack it tightly into a clean jar or tub, pressing out the air and leaving 3 cm of headspace.
6. 6
   Leave at room temperature for 1–2 days, until it smells sour and small bubbles rise when you press it, then refrigerate. It is good after a week and keeps for months, growing more sour as it ages.