1. Combine the flour and milk in a jar with a tight-fitting lid, and shake until smooth. Set aside.
2. Pour the turkey drippings from the roast turkey breast into a fat separator cup. (If you don't have a separator cup, pour the drippings into a bowl, add a few ice cubes, and skim off the fat once it rises and hardens.) Pour the fat-free drippings into a 2-cup measure, and add enough water to bring the volume up to 1 3/4 cups.
3. Pour the drippings mixture into a 1 1/2-quart saucepan, and add the bouillon granules and seasonings. Bring the mixture to a boil over medium heat, reduce the heat to low, and simmer for 5 minutes.
4. Slowly stir the flour mixture into the gravy, and continue to cook and stir until the mixture is thickened and bubbly. Transfer the gravy to a warmed gravy boat or pitcher.