Tie each piece of veal shank around its middle to secure the flesh, then dust with the seasoned flour. Heat the olive oil, butter and garlic in a large heavy roasting pan, big enough to hold the shanks in a single layer. Put the shanks in the pan and cook for 12 to 15 minutes until well browned. Arrange the shanks, standing them up in a single layer, pour in the wine and add the bay leaf, allspice, cinnamon and citrus juices from the lemon and orange prepared for the gremolata. Cover the saucepan.

Cook at a low simmer for 15 minutes, and then add ½ cup warm water and the beef stock. Continue cooking, covered, for about 45 minutes to 1 hour until the meat is tender and you can cut it with a fork; the timing will depend on the age of the veal. Check the volume of liquid once or twice; add more warm water and wine as needed. Transfer the veal to a serving platter or plate and keep warm. Discard the garlic cloves and bay leaf.

To make the gremolata, mix together the zest of the lemon and the orange, parsley and garlic. Increase the heat under the saucepan containing the veal and stir for one or two minutes until the sauce is thick, scraping up any bits off the bottom of the saucepan as you stir. Stir in the gremolata. Season with salt and pepper if necessary and return the veal to the sauce. Heat thoroughly, then serve with lemon wedges.