Source: Martha Stewart
adapted by http://theresalwaysthyme.blogspot.com/
makes 1 cup
2 vanilla beans, split lengthwise
1 cup unflavored vodka
Place vanilla beans in a clean jar with lid. Pour vodka over beans, and place lid on jar. Allow to sit in a cool dark place for 3 to 5 months, shaking jar occasionally. Keep topping off the jar with more vodka and add more beans to have a continued supply.