Pour the plain flour in a deep plate and coat the shanks on all sides with it. Season them with a dash of pepper and salt. You can tie them up as well if you want the meat to stay together but that’s not necessary.
In a large non-stick pan add a generous splash of olive oil together with the fresh rosemary sprigs.
Place the pan over high heat. Once the oil is hot, add the floured shanks to the pan.
Brown them on both sides for a couple of minutes. In the meantime dice the celery, the carrot, the yellow onion and 3 of the garlic cloves finely. Add them to the shanks as well. Season again with a good dash of pepper and salt.
Stir and add the tomato paste and chopped tomatoes to the browned shanks.
Then pour in the beef stock and the white wine.
Give the shanks a good stir and put a lid on the pan. Bring it all to a good boil and then turn the heat low. Braise the shanks in the tomato sauce for at least 4 hours until the meat is super smooth and tender. You can also prepare this dish in a slow cooker if you have one. Right before serving, make the gremolata: combine the grated lemon zest, the remaining chopped garlic clove and the freshly chopped parsley. Sprinkle this on top of the ossobuco once it’s plated up and ready to be served. Enjoy!