Mix together graham cracker crumbs, sugar, ground vanilla bean powder and butter, then press into the pie or spring form pan. Bake for 15 minutes or until crust is golden brown. Place on rack and allow to cool completely.
Using a food processor or a stand or hand-held mixer, blend pie ingredients well, making sure that all cream cheese lumps are blended. Pour into the cooled crust and refrigerate for at least four hours.
About 20 minutes before serving, whip cream and spread over pie. Refrigerate until ready to serve.
Be sure to use full-fat cream cheese for this recipe as the lower-fat cream cheese will be too soft. Adapt the lime juice and zest to taste. Key limes are tarter than Persian limes.