What you'll need:
Coffee maker (I use an aeropress)
Ice cubes (I use plastic ice cubes to prevent watering down my coffee)
4-5 oz. of water
Sparkling water (perrier, san pellegrino, etc)
and your favorite mug
Spoiler alert: we are going to add sparkling water to the coffee, because of this we want to brew it to be very strong, so use about twice the ratio of coffee to water as you normally would.
Since we're only brewing about 4 oz of coffee, I use the same amount of coffee that I would normally use for an 8 oz cup.
If you're using an AeroPress, like I did, brew the coffee for a little longer than you usually would and at a slightly higher temperature to prevent under-extraction. If you're using a standard drip coffee maker, don't worry about any of that snobbery.
You can also get this drink at any coffee shop, just get a double shot of espresso over ice and add the sparkling water.