Shred cabbage with a mandolin or rough chop in a food processor. It should be a little coarser than you would use for a cole slaw. (Be careful with the food processor - they can over-process really quickly).
Mix all the other ingredients in a microwaveable dish and warm together,
Place cabbage in a large slow cooker. Pour mixture over the cabbage and stir to coat.
Add about 1/2 cup of water to the slow cooker.
Cover and cook on low about 7 hours.
About 1/2 hour before serving check to adjust seasonings. Add more salt and vinegar if you want it tangier. The vinegar will also help keep the colour vibrant.