Combine brown sugar, cinnamon stick (if using), and ½ cup water in a small saucepan over medium heat.
Cook, stirring constantly, until sugar crystals are dissolved and syrup is hot. (Do not boil.)
Let cool, then remove cinnamon stick.
Prepare Drink:
Combine espresso and 1 ½ to 2 tablespoons simple syrup in cocktail shaker. Stir until combined.
Fill cocktail shaker half full with ice. Cover and shake for about 10 to 15 seconds.
Fill a tall glass ¾ full with ice. Strain coffee mixture into glass (discard ice from shaker).
Top drink with oat milk and a pinch of cinnamon, if desired.
Serve immediately. Enjoy!
Notes
Don't forget to check out the info before this recipe card for more tips, tricks, and recipe variations!Make sure to cool simple syrup before using. The recipe makes enough syrup for multiple drinks, and you can make it ahead of time, if you prefer.To make the oat milk extra thick and creamy, shake it for a few seconds before measuring it. You can do this right in the container it comes in. It should be a little frothy looking when you pour it.Espresso can be prepared using an espresso machine, a Nespresso machine (with espresso pods), or a moka pot (I have this Primula pot). You can also make this drink with strong coffee or with cold brew.Starbucks makes this drink with Oatly oat milk and their Blonde Roast Veranda Blend Coffee (which is available ground or whole bean, as well in pods for the Nespresso Virtuo or original system).