Begin by chopping your chocolate into small pieces and placing in a heat safe bowl.
Add cream, espresso, butter, and a small pinch of salt to a small pot and bring to a boil. Once it hits a boil turn off the heat and let it sit for a minute before pouring over the chocolate. Let the chocolate sit and melt for 5 minutes before stirring.
Once the chocolate is smooth, pour into a small tray lined with parchment paper. I used two quarter sheet trays and poured until the chocolate was around 1″ or 2.5cm tall.
Place in the fridge for two hours then into the freezer for an hour prior to cutting.
When the chocolate is firm pull it out of the freezer and remove from the tray. Dust the top with cocoa powder and cut into squares. Dust another tray or plate with more cocoa powder and place the truffles on top. Place in the fridge and after 30 minutes these are ready to eat.