Put instant coffee, sugar, and boiling water in a bowl and stir with a spoon until the coffee is dissolved. Whip with an electric mixer until the mixture becomes creamy and forms a firm foam. Put the ice cubes in a glass and pour milk over the ice cubes. Put the coffee foam on top of the milk in the glass. Voilá!   Stir in the glass before drinking so that it becomes a delicious creamy consistency.