Wash the apple, cut it in half, cut out the core and cut the apple halves into slices. Pour the Calvados over the apple slices and let them steep for about 30 minutes. Cut open the vanilla pod and scrape out the pulp.
Add pulp and pods to the apple juice. Remove the apple slices from the Calvados and bring to the boil briefly with the apple juice. Sweeten to taste with some sugar and remove the vanilla pod. Add the Calvados and pour the punch with the apple slices hot into glasses.