In the large sauce pan, begin melting the chocolate over medium heat. When it's about half melted, add the cream, butter, espresso powder, and Kahlúa. Continue cooking and stirring until the mixture is smooth.
Pour cooked mixture into the other bowl and chill for 4 hours or until firm.
Scoop out one teaspoon of the mixture at a time, forming into balls. Roll the balls in the cocoa powder. Press one half espresso bean into the top of each and place the balls on the baking sheet. Chill truffles for 1 hour or until firm.
Keep in airtight container in refrigerator for 2 weeks.