In a small bowl, whisk together the granulated sugar and the cinnamon until it is evenly mixed. You can also use a fork if your whisk is too big for the task.
Store in a Mason jar or an airtight container.
Notes
Feel free to add more cinnamon to make the cinnamon sugar more flavourful. It's up to you!
Play with the spices: instead of cinnamon, try ground cardamom!
Vary the sugar: classic cinnamon sugar calls for granulated white sugar, but you could try maple sugar for more flavour.