You sure can! Just make sure to use it ahead of time, so the syrup can cool. Start by using a small sharp knife to slice open a vanilla bean lengthwise, then gently scrape out the vanilla bean seeds from the pod. Add the seeds to the sugar water and give it a stir. In a small saucepan over medium heat, combine 1 cup granulated sugar, ½ cup water, and the vanilla bean seeds. Bring to a gentle boil and cook until the sugar has dissolved. Make sure to stir the entire time.