1.Put the two ham hocks in a large pot and cover with cold water. Add the stock powder and bring to the boil. Reduce the heat, skim the scum from the top of the pot, and continue to cook for 45 minutes until the meat softens.
2.Add the carrots, courgettes, beans and lentils to the pot, return to the boil and cook for a further 15 minutes. Remove the hocks, allow to cool a little and shred the meat (discarding the fat and skin) into 6 soup bowls.
3.Roughly chop the spinach and add this to the soup pot, along with the mung bean sprouts.
4.Season to taste, then ladle the soup over the meat in the bowls. Serve with the warmed or toasted sourdough bread.