In a small mixing bowl, combine the instant coffee, sugar, and hot water.
Using the hand electric mixer on high speed beat the mixture until thick, frothy for about 5-6 minutes.
Pour oat milk with ice cubes into a tall glass. Gently transfer the whipped coffer on top of the milk. Sprinkle with cinnamon. Enjoy! Note: For sugar free version: Use 2 Tbsp of Allulose in place of granulated sugar.