Warm the stock on the stove top.

Melt butter in a large sauce pan. Add flour and whisk to incorporate. Cook over medium low heat for 5 minutes whisking frequently, do not let it brown.

Slowly add the turkey stock, whisking to incorporate. Add the Gravy Master. This will deepen the flavor and darken the color. Continue cooking on a low heat for an additional 20 minutes or until the flavor of the flour has disappeared.