Question: My mother used to make a beef soup with beef shanks.
The meat was removed from the bones after cooking and served with red wine vinegar.
Any recipes for something like this?
Answer: There are many variations regarding how to serve the beef shank you used to prepare a homemade beef broth, such as your mother's recipe suggest.
Personally I have never heard of somebody's recipe using just vinegar, and I found nothing also doing a research about this way of serving it.
I can only suggest you the way my mother-in-law uses to serve it: pass the beef shank pieces on all purpose flour and fry them in olive oil. It is not a long cooking, just to add a crispy surface, as the meat is already cooked. Serve with lettuce salad.