Granted, when I have a coffee-based cocktail, it's either winter time and I'm drinking it steaming hot, or I'm just drinking straight Bailey's Irish Cream or Kahlua at room temperature. However, if the occasion arises that you're serving coffe-based cocktails on the rocks, using espresso ice cubes is the way to go.
As the espresso ice (these happen to be heart-shaped ice) melts, your cocktail doesn't get watered down. The Abstract Gourmet has an illustrated post, complete with recipe for an appropriate cocktail.
Brilliant.














