Haha it barely even takes a recipe. This was about a head of Napa cabbage and 8 cloves of minced fresh garlic- from a head, not pre-peeled.
Cut up the cabbage, put it in a clean, sterile, non-airtight container, add the garlic and about 3% by weight of salt, and knead it into the cabbage. Weigh it down or turn it every week and leave it in a cool, dark place. It's ready when it doesn't taste salty anymore, 3-5 weeks or so, but it can go longer. The more salt is added, the more sour the final product will be.
All kinds of things can be added. Black peppercorns, caraway, thyme, rosemary, other vegetables, etc.