The day before, add the dried beans to a bowl and cover with water. Let soak overnight, or at least 12 hours.
Make the broth – poke the cloves into the whole peeled onion. Add the onion, celeri branch, bay leaves, thyme and ham hock into a large pot over high-medium heat. Add about 4.5 litres (18cups) of water or enough to cover the ham hock. Bring the water to a bowl, lower the temperature to low and simmer for 1 hour, covered.
In a large frying pan, melt the duck fat over medium-high heat. Add the garlic, carrots, turnips and leek. Cook for about 6-7 minutes, stirring occasionally until the leek is translucent (but not caramelized yet).
After the one hour, add the vegetables and drained beans to the broth. Season with salt and pepper. Simmer for one hour, covered.
In the meantime, blanch the cabbage – heat up a medium pot of salted water and bring to a boil. Add the shredded cabbage and cook for 3 minutes until the leaves slightly soften. They should keep their vibrant color. Immediately transfer the cabbage to a colander and pass under cold water to stop the cooking process. Set aside to drain.
After the one hour, add the blanched cabbage to the soup and simmer for 30 minutes, covered. Add the potatoes to the soup and simmer for 30 more minutes, covered.
Remove the ham hock from the pot and transfer it onto a cutting board. Discard off the skin and excess fat and shred the meat with a fork; at this point the meat should fall off the bones easily. Return the shredded meat to the pot. Remove the clove-spiked onion, celeri and herbs from the pot. Discard the cloves and herbs, chop up the onion and celeri and place them back in the soup.
Cook for 15 more minutes with no lid and adjust seasoning if needed. To test the thickness of the soup, stick a soup ladle in the pot: if it stands upright on its own, it’s ready. If not, continue simmering the soup until it thickens more.
Serve in individual bowls with a light sprinkle of red pepper flakes and big slices of bread on the side.
