Coarse sea salt, for garnish, optional
For the braised veal shanks: Preheat the oven to 325 degrees F.
Heat the olive oil in a large enameled cast-iron Dutch oven over medium-high heat. Dredge the shanks in the flour, making sure to get off any excess. Add the shanks to the pan, in batches if necessary, and cook on all sides until browned, 3 to 4 minutes each side. Transfer to a plate. If browning in batches, repeat with the remaining shanks.
Add the onions, carrots, celery, coriander, 1 teaspoon salt, thyme, garlic, bay leaves, rosemary and chiles to the pan and cook over medium heat until softened, about 5 minutes. Add the tomato paste and cook, stirring, until glossy, about 2 minutes. Add the wine, scraping to deglaze the pan. Add the chicken stock and a pinch of salt and black pepper. Taste the simmering braising liquid at this point; it should taste seasoned. Return the shanks to the pan, cover and braise in the oven until the meat is very tender, 3 to 4 hours.
For the gremolata: When almost ready to serve, combine the parsley, olive oil, lemon zest and juice, salt and garlic in a small bowl. Stir to combine.
To serve, remove the shanks to a serving platter and spoon the sauce and braising vegetables over the top of them. Sprinkle with a little bit of sea salt and garnish with gremolata.