Combine the heavy cream and sugar in a mug or bowl and whip until soft peaks form - you can use a whisk, hand beater, or even a milk frother
Prepare 1-2 shots of espresso (depending on how your preferred strength
Add the hot water and creme de cacao to the espresso and combine (Note: make sure the water is very hot, as the whipped cream will cool the drink quickly)
Put dollops of whipped cream on top the coffee and garnish with cocoa powder, chocolate shavings, or a cinnamon stick
Notes
Your beverage should have equal parts of liquid and whipped cream.If you don't want to make the coffee alcoholic, you can use a coffee flavoring syrup or even some Hershey's syrup (but you might want to cut back on the sugar in the whipped cream to offset the extra sweetness).