Melt butter in a medium-size saucepan over medium heat, about 1 minute. Add 1 can of the broth; bring to simmer.
In a large measuring cup or bowl with a pouring spout, whisk remaining can of broth, gravy starter and flour.
Pour flour mixture into simmering broth while stirring. Add salt, poultry seasoning and pepper.
Increase heat to medium-high and bring mixture to a full boil. Once boiling, cook 3 minutes, until thickened. Transfer to gravy boat and serve warm. Makes about 3-1/4 cups.