Make a paste of the parsley, chives, tarragon, bay leaf, shallot, nutmeg, salt, and pepper. Add just enough oil to form the mixture into a paste. Rub the mixture all over the veal loin. Cover and refrigerate for at least 3 hours or overnight.
About 30 minutes before cooking, bring the roast to room temperature. Preheat oven to 425°F. Roast for 45 to 60 minutes or until an instant-read thermometer inserted in the thickest part of the roast registers 145°F.
Transfer the roast to a heated platter and cover loosely with foil. Discard the fat and scrape the fine herbs into a small saucepan, along with any pan juices. To this mixture, add broth as necessary. Adjust seasoning, adding wine vinegar, salt, and pepper to taste. Carve the roast, then spoon the sauce over the meat.