In a small bowl, combine the sugar, instant coffee granules, and boiling water. Beat the mixture with a whisk or an electric hand mixer until the coffee is like whipped cream (about 3 to 5 minutes). You can err on the side of soft peaks or go for something more stiffly whipped. Set the bowl aside.

Fill a glass with ice cubes and milk (you can use warm milk instead), then dollop the mixture of whipped coffee on top and mix before serving.