Put the cabbage, carrots and shallots or onions in a large mixing bowl.
Add the salt to half a cup of water and pour over the vegetables and massage with your hands for around 10 minutes, until the liquid is released (the brine)
Then add the remaining ingredients and massage again.
There should be plenty of liquid/brine now.
Tightly pack the mixture into a 1 litre jar that has been sterilised (pour boiling water over it and allow to cool)
The brine should cover all the vegetables. If not add more salted water (using 1 tsp. sea salt for every cup of water)
Use the outer layers to form a seal on the top.
Cover the jar and allow to ferment.
Taste after 3-4 days. If it is slightly vinegary, it is ready, otherwise leave it to continue fermenting. It can take up to 4 weeks depending on the temperature of your room.
When ready, seal and store in the fridge.