You will need a clean 4-oz glass bottle and its cap. I use a Boston round glass bottle.
Start by slitting each bean lengthwise and then cutting each bean in half. Place the beans into the bottle. Add the 1/2 cup of vodka. Cap the bottle tightly and place it out of direct sunlight and away from extreme temperatures. A pantry or kitchen cabinet is the perfect location. Now, sit back and wait! That's it..no more work!
The vanilla-vodka mixture will be clear for the first 3 days or so. Gradually, you will see that the mixture turns an amber color, and then dark brown. Optimally, you should wait at least 30 days to use the vanilla extract. Once it's ready, it will keep for about 12-15 months.
If you're going to give this as a gift, you may want to use a sticky label and either hand-write or (if you're feeling fancy!) use a graphics program to create a product label for your extract.