For the Brennsuppe mit Brieswürferln poach the sweetbreads (pour boiling water over them), remove the skins and sinews and cut into cubes the size of a thumbnail. Roll the sweetbread cubes in a little flour. Heat the clarified butter, fry the floured sweetbread cubes in it until crispy all over and keep warm.
Add the remaining flour to the clarified butter and quickly stir to make a roux. Gradually pour in beef broth and simmer on low heat for 10 to 15 minutes. Season to taste with salt, pepper, caraway seeds and apple cider vinegar. Serve the sweetbread cubes in warmed soup bowls, pour on the hot roux and garnish with chopped parsley.