01 - Place the chopped dark chocolate in a heatproof bowl.
02 - Warm the heavy cream in a small saucepan over medium heat until just simmering without boiling.
03 - Pour the hot cream over the chopped chocolate, let stand for 1 minute, then gently stir until smooth and fully melted.
04 - Add the unsalted butter to the chocolate mixture and stir until glossy and well combined.
05 - Cover and refrigerate for 1 to 2 hours until firm but scoopable.
06 - Using a teaspoon or melon baller, quickly scoop and roll portions of the chilled mixture into small balls between your palms to prevent melting.
07 - Roll each truffle lightly in cocoa powder placed in a shallow dish to coat evenly.
08 - Arrange truffles on parchment-lined tray and refrigerate for at least 30 minutes before serving.