Use a sharp knife to split each vanilla bean lengthwise, exposing the vanilla bean seeds inside. You don't need to scrape out the seeds separately. If the beans are too long for your bottle, cut them in half so they fit in the bottle and can be fully submerged.
Add the vanilla 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 (like your kitchen pantry), shaking once per week to distribute the vanilla. As the vanilla infuses, the vodka will gradually turn a deeper brown and develop more vanilla aroma. The vanilla extract will be ready to use after at least 8 weeks, but you can let the extract sit longer for a stronger flavor. The exact color and strength will vary depending on the beans and how long they infuse.
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Notes
The nutrition information shared is for the full bottle of vanilla extract. This will also vary based on the type of vodka (or other spirit) used. While this recipe takes just 10 minutes to bring together, be prepared that the vanilla extract will need to infuse for at least 8 weeks to develop a basic flavor before use.