Strain pan juices into large measuring cup, pressing on solids with back of spoon. Spoon fat from pan juices. Add enough chicken broth to pan juices to measure 3 cups. Transfer liquid to heavy medium saucepan and bring to boil. Mix 3 T. reserved maple butter and flour in small bowl to form smooth paste. Whisk paste into broth mixture. Add chopped fresh thyme and bay leaf. Boil until reduces to sauce consistency, whisking occasionally, about 10 minutes. Mix in apple brandy, if desired. Season gravy to taste with salt and pepper. Brush turkey with any remaining maple butter and serve with gravy.