A long time ago, just as I was starting to branch out in the world of baking, I read the brilliant idea about saving used vanilla bean pieces in sugar. Since I was just starting I didn't use vanilla beans so didn't care much. Well, the idea came back with a vengeance the first time I paid for a vanilla bean (ouch). I now buy vanilla beans in bulk, so I employ this trick to stretch my purchase (and flavor) as much as possible.
Vanilla is serious business to me. Slitting the bean down the center and scraping out the microscopic seeds is absolute bliss for me, but not having a purpose for those spent pods, which contain so much flavor, would be detrimental. When I am making jam or ice cream, or something similarly wet or sticky, I will just toss in the pod after scraping out the seeds to further infuse with the luscious flavor, discarding the pod once the cooking is complete. However, when I am only using the seeds, such as when I am making baked goods, I save the spent pods in sugar.
Once the seeds are scraped out I cut up the pod into smaller chunks and toss them into a sterilized jar and measure some sugar into the jar. Today, I only used half a vanilla bean, so I added it to the jar of vanilla sugar I already had and added about 1/2 c. sugar to the jar and shook it up to blend. The sugar will absorb the flavor and scent of the vanilla bean. The pod pieces will become dry and brittle, but no matter, just leave them in the jar until you're ready to use the sugar.