Carefully cut the vanilla beans in two, lengthwise. You can also cut them into halves so they are shorter and fit better into the bottle or jar.
Insert the vanilla beans into a clean glass bottle or jar.
Pour either 1 cup of vodka or 1 cup of glycerine in the bottle. Make sure the vanilla beans are completely submerged. Shake well.
Store in a dark corner (in a cupboard) at room temperature. Let sit for at least 6-8 weeks before you use it. Some even keep it for months or even a year. *
Notes
*This extract can be replenished continuously. Simply top up the bottle with alcohol every time you use some extract and make sure that the vanilla remains fully submerged under the liquid.