Place the cabbage, beetroot, carrot and onion into a bowl.
Add the sea salt and mix well. Lightly massage the salt into the vegetables. Let sit for about 15 minutes.
Add the caraway seeds, garlic and ginger and mix well.
Place a place and a weight (such as a jug of water) on top of the vegetables. Leave to sit for at least 2 hours or until the liquid is released and covers the vegetables.
Place the vegetables and the liquid into a clear mason jar. Pack the vegetables well into the jar with a wooden spoon. Leave a small space at the top of the jar.
Place the two cabbage leaves on top and push the vegetables down again. The liquid should cover the vegetables at all times.
Secure with a lid and place in a cool, dark spot in your kitchen for 3-5 days. Once fermented you can remove the whole cabbage leaves.
Store in the fridge and enjoy as a delicious addition to any meal.