For Creme Fraiche: Blend together sour cream and heavy cream. Chill several hours. Coat chicken with mustard. Cover and chill for 2-8 hours. Preheat oven to 350 degrees. Arrange chicken in baking dish and season with pepper. Pour wine around chicken. Bake 30-40 minutes or until chicken is done. Transfer chicken to serving platter and cover to keep warm. Transfer juices and mustard from baking dish to sauce pan. Bring to boil and whip in Creme Fraiche. Simmer 5-10 minutes. Season lightly with salt and pepper. Spoon over chicken and serve. Bon appetit!