Remove wilted outer leaves and set one clean leaf aside. Quarter the cabbage, remove the core, and slice thinly.
Place in a large bowl, sprinkle with salt, and massage for 5–10 minutes until it softens and releases liquid.
Pack tightly into a clean jar, pressing down until liquid covers the cabbage.
Use the reserved leaf to keep it submerged and add a weight if needed.
Cover loosely with a lid or cloth and place on a plate to catch overflow.
Ferment at room temp for 5–14 days. Start tasting on day 5. Once tangy, refrigerate.
Store in the fridge and enjoy for weeks or months.