01 - Place chopped chocolate in a heatproof mixing bowl and set aside.
02 - Pour heavy cream into a small saucepan and heat over medium heat until it just begins to simmer. Do not boil.
03 - Pour hot cream over chocolate and let sit for 2 minutes. Gently whisk until chocolate is completely melted and mixture is smooth.
04 - Add softened butter and vanilla extract. Stir until mixture becomes silky and glossy.
05 - Cover bowl with plastic wrap and refrigerate for 2 hours or until firm enough to scoop.
06 - Using a teaspoon or small melon baller, scoop portions of ganache and quickly roll between palms to form balls about 1 inch in diameter.
07 - Place cocoa powder in shallow bowl. Roll each truffle in powder until evenly coated.
08 - Store in airtight container in refrigerator up to 1 week. Bring to room temperature before serving.