How to Make It
Season the veal shanks with salt and pepper. Dust them with flour, shaking off the excess. In a large skillet, heat the olive oil. Add 5 of the veal shanks and cook over moderate heat until richly browned, about 4 minutes per side. Transfer the shanks to a roasting pan that's large enough to hold them all in a single layer without crowding. Repeat with the remaining shanks.
Preheat the oven to 300°. Add the carrots, celery and onions to the skillet. Cover and cook over moderate heat, stirring occasionally, until softened, about 12 minutes. Add the wine and boil uncovered over high heat until reduced to 1/3 cup, about 5 minutes. Stir in the water and tomato paste and bring to a boil. Pour the contents of the skillet over the shanks.
Cover the roasting pan with foil. Transfer the shanks to the oven and braise for 2 hours and 45 minutes, or until the meat is very tender. Transfer the shanks to a large, rimmed baking sheet. Discard the strings and cover the shanks with foil. Increase the oven temperature to 350°.
Strain the liquid from the roasting pan into a large saucepan, reserving the vegetables. Boil the liquid over high heat until reduced to 4 cups, about 25 minutes. Return the vegetables to the sauce and season with salt and pepper.
Meanwhile, reheat the veal shanks in the oven until hot, about 7 minutes. Transfer the shanks to plates, ladle the sauce on top and serve.