Make ice cubes out of espresso to seriously rev up your iced coffee (and your heart rate). Get some espresso, or make your own, and fill an ice tray or two with it. Let the trays freeze overnight, then use them in the morning with a strong pot of your favourite coffee.For the truly adventurous (or seriously addicted) out there, you can try using a couple of espresso ice cubes in a cup of cold-brewed coffee. I know I will.
Iced Coffee 101 [food52]