Combine all ingredients except cinnamon in cocktail shaker. Shake. Serve up on a glass rimmed with cinnamon sugar or garnish with a dash of cinnamon.
Can sub the cold brewed coffee for a coffee liqueur to make this extra potent.
I used hot damn cinnamon schnapps (because its what I had on hand), but a cinnamon simple syrup would work here as well.
Tasters were split 50/50 on a sugar rim vs. dash of cinnamon on top.