01 - Place the chopped chocolate in a heatproof bowl.
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 sit for 2 minutes to melt, then gently stir until smooth and glossy.
04 - Add the butter and vanilla extract, stirring until fully incorporated.
05 - Cover the bowl with plastic wrap and refrigerate for at least 2 hours, or until the ganache is firm enough to scoop.
06 - Line a baking sheet with parchment paper. Using a small spoon or melon baller, scoop out heaping teaspoonfuls of ganache and roll quickly between your palms to form balls.
07 - Place the cocoa powder in a shallow bowl. Roll each truffle in the cocoa powder to coat evenly.
08 - Place coated truffles on the prepared baking sheet. Chill for 20–30 minutes to set, then store in an airtight container in the refrigerator.