Over high heat brings water to boil with the shank and bay leaves. As soon as it comes to a boil turn down the to medium-low, cover and let it simmer for a minimum of an hour to several hours. You can also use boxed beef broth but this is less expensive and can be done overnight.
While the broth is cooking, peel the raw beetroots. Make sure to use gloves as your fingers will be stained. Save the skins.
Cut the beetroot into quarters and slice into 1/2 cm-1cm pieces.
Once the broth is ready throw in the beet pieces. Make sure cook on low heat. Cook for 45 minutes or until the beets are tender.
In a smaller pot add in the beetroot skins, cover with water. Cook over low heat
Once the beets are tender, drain the beet skin stock, using a sieve into the stock pot with the beets. Add the herbs de provence or thyme as well as the apple cider vinegar or lemon juice. Let it cook for a little bit more and taste to make sure that the sourness is too your liking. You can always add more.
Add pepper and salt to taste. Serve hot, in a soup bowl or in a cup.
This soup holds well in the refrigerator, over time it grows slightly tangier.