Fricassée de Poulet au Vinaigre de Framboise (Chicken with Raspberry Vinegar)

Poulet au vinaigre may be traditional, but it’s scarce and perhaps nonexistent in French cookbooks published before the 1970s, when it was taken up by the three-star chefs Charles Barrier and Jean Troisgros and then others. (The likely predecessor to the dish, rather than vinegar, uses verjuice, the juice of grapes chosen for their strong acidity.) It w…