In a popsicle mold, add 2 tablespoons of oat milk into bottom of 4 molds. Place into freezer for 1.5 hours.
Meanwhile, in a small sauce pan, bring water to a boil. Once boiling, remove from heat and add brown sugar and cinnamon. Stir until sugar is dissolved (cinnamon will not dissolve). Allow to cool while oat milk begins to freeze.
Next, brew choice of coffee or espresso. Add vanilla and allow to cool.
After 1.5 hours, remove popsicle mold from freezer. Evenly distribute coffee between 4 popsicle molds.
Next, top coffee layer with even amounts of brown sugar syrup. Cover with popsicle mold cover and insert popsicle sticks.
Freeze for at least 6 hours or overnight. To easily remove from popsicle mold, run briefly under warm water and push out. Enjoy!