In a cup or a deep bowl, add the instant espresso, 2 teaspoons of sugar, and 2 teaspoons of hot water. Turn an electric whisk on medium speed and whip the coffee until it triples in volume and is frothy, about 2-3 minutes. Set aside.
Add the remaining 2 teaspoons of sugar to the 2 teaspoons of hot water to make a simple syrup. The water should be hot enough so that the sugar fully melts.
In your coffee cup, add the ube extract, coconut milk, and simple syrup. Stir it well with a spoon.
Fill the cup with ice. Pour the milk over the ice. Then, pour the frothy espresso over the milk. Give it a really good stir. Enjoy!
Substitute the coconut milk and simple syrup with sweetened condensed milk.