1 cup (250 mL) vodka (rum, bourbon, or brandy may be used; vodka produces the cleanest-tasting extract)
Instructions
Split vanilla beans lengthwise with the tip of a knife, stopping about 1-inch from one end. (Use vanilla beans that are soft and flexible). Place beans in an 8 to 12-ounce jar with a lid. Some people scrape the seeds add the scrapings and beans to the jar separately, but I don't bother scraping.
Pour vodka over the beans to nearly the top of the jar, about 95% full. Seal jar, shake vigorously for about 30 seconds, and set in a cool, dark place, where jar will stay for two months. Once or twice per week, shake the jar for about 10 seconds, otherwise just forget about it.
In 6 weeks, the extract may be ready to use, but it will likely take 8 weeks, and longer is better as the extract will continue to mature. As time passes, the alcohol will fade and the flavor of vanilla will develop and strengthen. Use your nose and if it smells strongly like alcohol, it's not ready. The extract will always have some scent of alcohol, but it should smell mostly like vanilla. You will be able to tell if it's ready with your nose.
Recipe by Kiku Corner at https://www.kikucorner.com/2014/12/18/diy-how-to-make-vanilla-extract/