Shred the cabbage using a food processor or by hand.

Combine the cabbage and salt in a bowl and allow this to sit for 30 minutes so that the natural liquid from the cabbage is released. You can also pound the cabbage with your hands to help release the natural juices.

While the cabbage sits, prepare the remaining ingredients.

Using a coffee grinder, freshly grind the coriander seeds, fennel seeds, cumin seeds, fenugreek seeds, black peppercorn and cardamom seeds.

Add the freshly ground spices, onion, garlic, and turmeric powder to the cabbage and mix well.

Using a wooden spoon, pack the cabbage into a 1 quart mason jar (or fermentation crock). The cabbage should be tightly packed so that it remains underneath its own brine.

Place cheesecloth over the mason jar, securing with a large rubber band.

Place the jar on top of a tray and allow it to sit in a dark place for 1-3 weeks, or until it reaches your desired level of sourness, then refrigerate.