In a coffee mug, add the cocoa powder. Pour in the hot coffee and stir. Add the Puremade Pumpkin Spice Syrup and stir. Heat oat milk for 30-40 seconds in the microwave and froth using frother. Add the oat milk on top of the coffee. Top it all off with marshmallow fluff (or whipped cream) for an indulgent mocha treat!