You can easily make your own oat milk, but again, I prefer to buy mine.
If you prefer to add brown sugar simple syrup, prepare it ahead of time. Combine brown sugar and water in a saucepan over medium heat. Stir the mixture and heat until the sugar dissolves. Do not allow the mixture to boil. Set it aside and store in a mason jar for later use.
Prepare your espresso or coffee of choice and set it aside.
In a saucepan or heated milk frother, add your oat milk, maple syrup, and cinnamon. Heat and froth until warmed through.
Pour your coffee or espresso into a mug.
Add your oat milk mixture to your coffee mug.
If you are using brown sugar simple syrup, pour it in now to taste.