Pour off fat from turkey roasting pan and place pan on burner/s. Add 2-3 tablespoons flour to liquid and let it brown. Then add the water from the potatoes (you will be having mashed potatoes won’t you?) and thicken some more, if necessary, with a mixture of flour and water. Grandma usually mixes the flour and water in what looks like a cocktail shaker but I never saw it used for cocktails.