Cut your vanilla beans in half lengthwise to expose the vanilla bean seeds. Make sure the vanilla beans are short enough to fit into your bottle (cut them in half, if needed!)
Add the beans to the bottle. Pour vodka into the bottle to cover the vanilla beans completely.
Close the bottle and shake! Store in a cool, dry place, shaking once per week to distribute the vanilla. They're ready to use after at least 8 weeks, but you can always let them sit longer for a stronger flavor!