01 - Place the chopped 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 chocolate and allow it to sit for 2 minutes to soften.
04 - Add the butter and vanilla extract, then gently stir with a spatula until the mixture is smooth and glossy.
05 - Cover the bowl with plastic wrap and refrigerate for 2 hours until firm enough to handle.
06 - Sift the cocoa powder into a shallow dish.
07 - Using a melon baller or teaspoon, scoop the ganache and quickly roll between hands to form 1-inch diameter balls.
08 - Roll each ganache ball in the cocoa powder until fully coated.
09 - Place coated truffles on parchment paper-lined tray and refrigerate at least 15 minutes before serving.