Among experienced cooks, it's well known that the toughest cuts of meat are generally the most flavourful, because they are dense and have a lot of connective tissues. Beef shin, or shank as it's also known, is a perfect example of that principle. A piece of grilled shin would be inedibly tough, but when slow-cooked it becomes lusciously rich and tender.
Preheat the slow cooker on its high setting.
Place the onion, carrot and celery in the bottom of the slow cooker, to make a pad for the beef to rest on. Place the piece or pieces of shin on the vegetables, and add the rest of the flavourings.
Pour enough red wine or beef broth into the cooker to submerge at least 2/3 of the shin. Cover and cook on high for approximately 45 minutes, until the cooker is steaming and aromatic. Do not let the cooking juices boil.
Reduce the heat to low, and cook until the shin is fork-tender. This will take six to eight hours for a single large piece of shin, or four to six hours for inch-thick slices.
Remove the meat to a serving platter and cover loosely with aluminium foil, to keep it warm. Strain the cooking juices and spoon the fat from the top. Use the juices to make a sauce, either by thickening with cornstarch or simply boiling them down until thick.
Slice and serve the shin with your favourite side dishes, and the sauce you've made from the cooking juices.
Potatoes, carrots or other vegetables can be added to the slow-cooker, creating an easy one-pot meal. If you do not have a slow cooker, or if it is too small to fit the beef shin, use the smallest roasting pan or Dutch oven that will fit the meat. Bring it to a simmer on the hob, then finish in your oven at 121 degrees Celsius until fork-tender.