Heat heavy cream in a double boiler (or a heat-safe bowl over a pot of simmering water) at medium heat, stirring occasionally. Heat until just about boiling (about 185-190°F) - you should see small bubbles on the surface.
Whisk in chocolate until melted. Remove from heat.
Stir in whiskey & espresso powder and mix until combined. Chocolate should be smooth and silky.
Allow to cool at room temperature for about 45-60 minutes, stirring occasionally.
Cover loosely with plastic wrap or a plate and chill in refrigerator until well set - at least 2 hours or overnight.
Scoop with a small cookie scoop (or a spoon) into 1T-sized balls. Roll in cocoa powder or sprinkles.
Store in an airtight container in the refrigerator for up to 5 days or freeze for up to a month.
Notes
Want a dairy free version? Use Coconut Cream!For a ~14oz can of coconut cream(make sure it's coconut cream, not coconut milk), use 14 oz of dark chocolate (check label to make sure it's dairy-free). You can reduce the amount of whiskey and espresso powder if you like (so about 2T +1tsp whiskey, and 1 1/4 tsp espresso), or leave the measurements as is for a stronger flavor.