How to Make It
Preheat oven to 350°F. Tie each veal shank once around the circumference so that it holds the bone and meat together in the center. Season the veal shanks with salt and pepper. In a shallow bowl, dredge the veal shanks in flour, and pat off the excess.
Heat the grapeseed oil until shimmering in a large enameled cast-iron casserole dish over medium. Add the veal shanks, and cook until well browned, about 5 minutes per side, adjusting the heat as needed to avoid burning the flour. Remove the shanks from the casserole, and set aside.
Add the carrots, celery, onion, and garlic to the same casserole, and cook over medium-high, stirring constantly, 2 to 3 minutes. Add the tomato paste, and cook for 5 minutes. Deglaze the casserole with the red wine. Bring to a boil, and cook until the wine is reduced by half, about 2 minutes. Stir in the veal stock and add the crushed tomatoes, thyme, rosemary, bay leaf, and parsley.
Return the veal shanks to the casserole, and bring to a boil over high. Once the liquid boils, cover, transfer to the oven, and cook for 2 hours to 2 hours and 30 minutes, until the meat is fork-tender and falling off the bones.
Remove the herbs from the braising liquid and discard. Using a skimmer or large spoon, skim off any grease or foam that rises to the surface. Season with salt and pepper.
To serve, cut and discard the twine from each shank. Transfer veal shanks to individual serving bowls, and ladle about 3/4 cup of sauce and vegetables over each shank. Garnish with lemon zest and chopped parsley. Serve with polenta.