Cut vanilla beans in half, crosswise. Split beans open and scrape seeds out. Add beans and seeds to cognac. Let set for at least 2 months, shaking bottle frequently. It will still have more of the cognac smell than it does a vanilla odor. The flavor cooks into the food as it bakes. This is very expensive and very good. You can buy American cognac which is much cheaper, but the results are not as good.
From Bessie Hulett in _Bessie's Blue Ribbon Recipes_ by Bessie Hulett.