Pour pan drippings from roasted turkey into a large measuring cup. Skim and reserve fat from drippings. Add chicken broth to the drippings to measure 2-1/2 cups total; set aside. Measure fat and add melted butter or margarine, if necessary, to make 1/2 cup.
Pour the 1/2 cup fat into a medium saucepan. Stir in the all-purpose flour, salt, and pepper. Cook and stir over medium heat for 2 minutes. Gradually whisk broth mixture into flour mixture. Cook and stir until thickened and bubbly. Add milk. Cook and stir 1 minute more. Makes about 3-1/2 cups (14, 1/4-cup servings).