How to Make It
In a large saucepan, bring the wine to a boil over moderately high heat. Remove from the heat and add the carrots, leek, garlic, parsley and thyme sprigs and bay leaf. Let the marinade cool. Spread the short ribs in a large shallow baking dish in a single layer. Pour the marinade over the ribs, cover and refrigerate overnight.
Preheat the oven to 300°. Remove the short ribs from the marinade. Strain the marinade, reserving the liquid and vegetables separately. Discard the herb sprigs and bay leaf.
Season the ribs with salt and pepper and dredge them in the flour. In a large skillet, heat 2 tablespoons of the oil until almost smoking. Add half of the ribs and cook over moderately high heat until well browned, about 4 minutes per side. Transfer the ribs to a large roasting pan. Brown the remaining ribs in the remaining 2 tablespoons of oil and add them to the roasting pan in a single layer.
Pour off all but 1 tablespoon of fat from the skillet. Add the reserved vegetables and cook over high heat until beginning to brown, about 4 minutes. Spoon the vegetables over the ribs. Add the marinade to the skillet and bring to a boil. Pour the marinade over the ribs and add the veal stock. Cover with foil and bake for about 3 hours, or until the meat is very tender and almost falling off the bone. Transfer the ribs to a large baking dish. Leave the oven on.
Strain the cooking juices into a large saucepan and skim the fat from the surface. Boil over high heat until reduced to 2 cups, about 15 minutes. Whisk in the mustard and season with salt and pepper. Pour the sauce over the ribs.
Return the ribs to the oven and bake for 30 minutes. Let cool slightly before serving.