Break up baking chocolate in small pieces, as small as you can get them, and place in large mixing bowl. Add brown sugar to the bowl as well.
Heat up heavy cream until nearly boiling (but don't let it boil).
Mix espresso powder and coffee liqueur into heavy cream until all combined and carefully pour it in the bowl with chocolate. Slowly whisk chocolate until all melted and smooth.
Set the bowl aside to set, away from any heat, for about an hour.
Scoop out about 1/2 inch balls with a spoon and lay them out on parchment paper covered board. Refrigerate for about 30 minutes.
Roll truffle balls with your hands to make them evenly round.
Sift cocoa powder and powder sugar together until all combined.