Preheat a 6-ounce heat-proof glass by filling it with hot water. Once warm, discard the water.
Add two sugar cubes to the glass, then add coffee until the glass is ¾  full. Stir until the sugar is dissolved.
Add 1 ⅓  ounces of whiskey to the coffee and stir gently and briefly to combine.
Float a layer of whipped cream over the top of the coffee by pouring it gently over the back of a spoon.