Make the espresso. Leave in a freezer to cool down.
Pick a glass and prepare other ingredients.
Add ice cubes to the glass.
Pour tonic water over the ice – ¾ of the glass.
Pour espresso over a spoon to separate the liquid for a prettier presentation.
Add the orange wheel to the glass (or a wedge).
Add brown sugar simple syrup if you want to add a sweetener.
Serve immediately and enjoy!
Notes
To make a brown sugar simple syrup:
Combine equal parts of brown sugar and water. I usually use 1 cup of brown sugar and 1 cup water.
Heat on medium heat until the sugar dissolves. Please make sure it does not boil.
Remove from heat and store it in a jar in a fridge for a few weeks.
Cool the espresso: When you make it, you need to cool it down because adding it immediately will melt the ice and warm the drink.
Pour ingredients slowly: When pouring the liquid, pour it slowly. Tonic water is very carbonated, so you want to avoid any over-spilling. To keep the layers separated, pour the espresso very slowly.
If you use a sweetener, add it at the very end because it will mix the layers, and the espresso will sink to the bottom.