In a medium bowl, combine the instant coffee, granulated sugar, and water. Using a hand mixer on high speed or a hand whisk, whisk until it turns into a frothy whipped topping. Otherwise, brew espresso-style coffee and cool it or use a concentrate like the one below.
Make the cocktail:
Prep the glass by filling it with ice. Add your preferred milk into the glass and then the tequila.
Spoon in the frothy coffee mixture on top or slowly pour the shot of espresso and stir to combine. Enjoy!