“This is an easy dish–roasted chicken with a very special sauce. The sauce itself can be made ahead and reheated at serving time so that you have time to do other things while the chicken is roasting.” –Stafford’s In the Field, Chocorua, New Hampshire
Sprinkle chicken with salt and pepper and tub all over with the softened butter. Place on its side in aw roasting pan and roast in a preheated 400 degrees F oven for 15 minutes, basting occasionally. Turn on the other side and roast another 15 minutes. Turn breast side up and roast 15-20 minutes longer, still basting. Remove the trussing string, place chicken on a platter, and keep warm. Pour off the fat that has accumulated in the roasting pan. Deglaze the pan with 1 cup of water. Melt all the solidified juices and pour into a saucepan through a fine strainer. Allow the liquid to reduce until it is as thick as jam. This is a meat glaze. Keep warm while you make the sauce.
Combine the first 4 ingredients in a saucepan and reduce by half. Mix the flour and butter together, add to the sauce, bit by bit, beating constantly with a wire whisk, then simmer slowly for 10 minutes. Add the champagne and bring to a boil; reduce for another 3-4 minutes and stir in the cream. Cook over medium heat for 5 minutes, strain the sauce, correct the seasonings, and stir in the cognac. To serve, coat the chicken with the sauce and drizzle the meat glaze over the top.