Divide milk between 2 serving glasses with ice. Set aside.
Add instant coffee, sugar, and hot water to a tall container. Whip using a hand mixer or immersion blender with whisk attachment for 1-2 minutes until it reaches a thick and creamy consistency.
Spoon the whipped coffee on top of the milk in the 2 serving glasses. Serve with a straw - it's best to stir as you go!