Preheat oven to 350 degrees F. Season quail, stuff with foie gras and wrap with bacon. In oven proof saute pan heat 2 tablespoons of the butter over moderate heat until hot. Add quail and cook until golden on all sides. Transfer to oven and roast 15 minutes. Transfer quail to a serving dish.
Discard all but 2 tablespoons fat from pan. Add shallot and cook, stirring, 1 minute. Deglaze pan with Armagnac, scraping up brown bits clinging to bottom of pan. Add veal stock and reduce to 1 cup. Add enough arrowroot to lightly thicken sauce. Whisk in remaining butter.
Pour juices from platter containing quail into sauce and stir to combine. Coat quail with sauce and garnish with chervil.
Recommended Wine: 1983 Gevrey-Chambertin, Clos Prieur, Domaine Rene Le clerc