Cut cabbage, brine in salt water 2–3 hours, rinse, and drain for 20 minutes.
Make paste: mix rice flour with water, heat until thick, cool; combine with gochugaru, fish sauce, garlic, ginger, and sugar. Taste and adjust the seasoning.
Mix cabbage, radish, and green onions with the paste using gloves.
Pack into jars; ferment 1–2 days at room temp, then refrigerate 3–5 days.
Serve in a white ceramic jar with sesame seeds, rice, and soju.
Notes
Use non-iodized salt for fermentation.
Store in the fridge for 1 month or freeze for 3 months.