Place the ice cream, eggnog and cinnamon in a blender. Blend until smooth.
Pour the mixture evenly into 2 serving glasses.
Top with the whipped cream and sprinkle extra cinnamon on top.
Serve immediately while cold and enjoy!
Notes
This is best served fresh, but you can store any leftovers in the freezer for 1-2 days. Let the leftovers sit at room temperature for 15-20 minutes and then stir to make it a shake consistency again before serving.