Braise them low and slow at 300°F for 3–4 hours in liquid (wine, stock, tomatoes, whatever you've got). Make classic Osso Bucco if you're feeling Italian. Throw them in a hearty beef stew. Braise them with vegetables and reduce the liquid into gravy.
The bone marrow in the center is a bonus. Scoop it out with a small spoon and spread it on bread. Your house will smell incredible all afternoon.
These shanks come from the leg, a hardworking muscle with lots of connective tissue. Cooked right, that connective tissue breaks down into gelatin, which makes the meat tender and the sauce rich.
Keep frozen until ready to use for up to 12 months. Thaw in the refrigerator overnight, or quick thaw in a bowl of cold water if you're in a hurry (just keep it in the sealed package). Keep thawed osso buco in the fridge for 1-2 days, or refreeze immediately if not using.