Preheat the oven at 325°F.
Season the chicken thighs on both sides with ample salt and pepper. Dredge the chicken breasts in the flour, coating both sides well but shaking off any excess.
Heat some of the oil on medium heat in the hot sauté pan and sauté the chicken for about 3-5 min until lightly browned on both sides. Reserve the chicken.
Add the bacon to the pan with a little butter if needed, and cook gently until light golden brown, reserve with the bacon. Add the onions to the pan and cook, stirring for about 6 min until lightly browned and add the cognac, stir well and then add the mushrooms and cook, stirring often until they have render most of their juices about 3 min.
Add the wine and the stock to the pan and bring to a boil over medium heat. Reduce the heat to medium for few minutes (5 min). Return the chicken and bacon in the pan; add the salt, pepper and the chervil. Cover and place in the oven until the chicken is tender, 15-20 min.