01 - Place the chopped chocolate in a heatproof bowl set aside while heating the cream.
02 - In a small saucepan, heat the cream over medium heat until it just begins to simmer. Do not boil.
03 - Pour the hot cream over the chocolate. Let it sit for 2 minutes, then gently stir until the chocolate is fully melted and smooth.
04 - Add the butter and vanilla extract, stirring until completely incorporated and glossy.
05 - Allow the ganache to cool to room temperature, then cover and refrigerate for at least 2 hours, or until firm enough to scoop.
06 - Line a baking sheet with parchment paper. Using a teaspoon or melon baller, scoop out small portions of ganache and roll into balls with your hands.
07 - Place the cocoa powder in a shallow dish. Roll each truffle in cocoa powder to coat evenly.
08 - Store the truffles in an airtight container in the refrigerator. Bring to room temperature before serving for best texture.