Remove turkey from roasting pan. Place strainer over small bowl. Pour drippings (turkey juices and fat) from pan into strainer. Skim 2/3 cup fat from top of drippings; place fat in 3-quart saucepan. Discard any remaining fat (or if there is not enough fat, add enough melted butter to fat to measure 2/3 cup). Reserve remaining drippings.
With wire whisk, stir flour into fat in saucepan. Cook over medium heat 1 to 2 minutes, stirring constantly, until mixture is smooth and bubbly. Remove from heat.
Measure reserved drippings together with broth; add enough water to equal 5 cups liquid. Gradually stir broth mixture into flour mixture. Heat to boiling over high heat (5 to 6 minutes), stirring constantly. Boil and stir 1 minute.