Split the vanilla beans lengthwise using a sharp knife, leaving the seeds inside intact but exposing them.
Place the split vanilla beans into a clean glass jar or bottle that has a tight-sealing lid.
Pour the vodka over the beans, making sure they are fully submerged in the alcohol.
Seal the jar or bottle tightly and shake it gently.
Store the jar in a cool, dark place for at least 2 months. Shake the jar every week or so to help the extraction process.
After the extract has matured, you can either leave the beans in the bottle or remove them. If you remove the beans, strain the extract through a coffee filter or cheesecloth into another clean bottle.