How to Make It
Heat the oil in a large enameled cast-iron casserole. Season the veal with 1/2 teaspoon each of salt and pepper. Flour the pieces and shake off any excess. Add the meat to the casserole and cook over moderately high heat, turning often with tongs, until golden brown on all sides. Remove the veal to a platter.
Add the carrots, celery, onion and garlic to the casserole and cook, stirring often, until softened, about 5 minutes. Set the veal on top of the vegetables and pour in the wine. Increase the heat to high and boil until almost all of the wine has evaporated. Add the chicken stock, tomatoes, thyme and bay leaf. In a small bowl, mix the tomato paste with 2 tablespoons of the cooking liquid. Add to the casserole along with the orange juice and bring to a boil. Reduce the heat to moderate, cover and simmer until the veal is very tender, about 1 1/2 hours.
Meanwhile, in a small saucepan, blanch the orange zest for 3 minutes to remove its bitterness.
Remove the meat to a large deep serving dish and cover with foil to keep warm. Increase the heat to high and boil the sauce until it is reduced by half and very flavorful, 20 to 30 minutes. Strain the sauce through a fine sieve into a medium saucepan, pressing gently on the vegetables; discard the solids.
Bring the sauce to a boil and stir in the orange zest. Season the sauce with salt and pepper, pour it over the meat and serve at once.