3 pounds beef shank bones
1 large onion, cut into 1-inch pieces
2 quarts purified water
3 tablespoons apple cider vinegar
3 celery stalks, cut into 1-inch pieces
1 carrot, cut into 1-inch pieces
4 sprigs fresh parsley
4 garlic cloves, minced
2 bay leaves
Preheat oven to 450ºF. Place bones and onion in a roasting pan. Bake for 30 minutes or until bones are browned. Remove from oven.
Place bones and onion in a large stockpot. Add water, vinegar, celery, carrot, parsley, garlic, and bay leaves to the stockpot and bring to a boil. Reduce heat, cover and simmer for 3 hours. Strain and discard vegetables and bones— save the meat for later use or another recipe. Refrigerate and use within 3 days, or freeze.