Season the lamb shanks generously with salt and pepper. Heat some cooking oil in a frying pan then cook the shanks over a medium-high heat until they are golden brown all over.
Remove them from the pan, then add in the carrot, onion, and celery and cook for 5 minutes or until it softens.
Add in the garlic, rosemary, and thyme, and cook for a further minute.
Add the vegetables into the slow cooker, then pour in the red wine, tin of tomatoes and tomato paste. Stir it well then get the lamb shanks in there too. They should be almost submerged, if they aren’t then add some water or stock.
Cook on HIGH for 4 hours or on LOW for 8 hours.
Once cooked, remove the shanks from the slow cooker, then blitz the sauce to a smooth consistency. Get the shanks back into the sauce and leave on WARM until you’re ready to serve.
Dish up the shanks with mashed potato, then spoon over a generous amount of the red wine sauce. Enjoy.