Seems like every culture has it own spin on fermented cabbage. Sauerkraut, kimchee and curtido? On a recent trip to Central America we were fascinated by cabbage relish served with the regional pupusas and really almost everything else. Every restaurant and food stall had a slightly different take on the recipe and all were deservedly proud of their results.
The secret to making it is to brining the cabbage in a solution of one tablespoon salt to every cup of water with a half a cup of vinegar. Cover thinly sliced (pelo de bruja) cabbage with brine and leave the mixture on the counter to ferment naturally a few days. You can eat it any time, but it will mellow and become more complex over time. Do put it in the fridge after a few days though.
You can add anything you like flavor-wise. Thinly sliced onions, carrots and oregano are traditional, garlic is always nice, peppers for heat … Oh right and the type of cabbage is not particularly important, but use red for its eye catching color.