Combine cider, bourbon, maple syrup and ice in a cocktail shaker or mason jar. Shake vigorously until well-combined and frothy.
If using, combine sugar and vanilla powder or cinnamon in a shallow dish. Lightly coat the glass rims with maple syrup and place in the sugar mixture to coat.
Strain cider-bourbon mixture into glasses and garnish each with a rosemary sprig. Serve.
Recipe by Baked In at https://www.baked-in.com/2014/10/19/apple-cider-and-bourbon-cocktail/