Heat half of the oil over medium-high heat. Add the flanken and the marrow bones and sear for three to five minutes per side. Remove the meat and bones from the pot and set aside.

Pour the rest of the oil into the pot and add the diced onions. Sauté for about 15 minutes until the onions are softened and golden. Add the bags of Beleaves vegetables and allow it to cook for 20 minutes.

Pour eight cups of water and add the meat, marrow bones, salt, and black pepper into the pot. Bring to a boil. Lower the heat and allow the soup to cook over low heat for two hours.

Remove the flanken and marrow bones and blend the soup until smooth. Shred the meat and place it back into the soup.