Combine cinnamon and vodka in an extra large jar. (Optional: Add 3 teaspoons of sugar to mixture to enhance the flavor and add a sweet touch)
Seal the jar and store in a cool, dark place for 5-7 days. Check on the jar each day, making sure to shake the jar once a day.
After 5 days, take a tiny taste - if the vodka is to your liking, pour the mixture through a fine-mesh strainer into a clean bowl or jar. Discard the solids. (If the flavor is not strong enough, allow cinnamon to infuse in vodka for a few more days, and return to step 3)
Return vodka to jar, seal and store in a cool, dark place until ready to use. Cinnamon vodka will keep for up to 1 year.