Finely chop the dark chocolate and place it in a heatproof bowl.

In a saucepan over medium heat, warm the heavy cream until simmering. Pour it over the chocolate and let it sit for one minute before stirring until smooth.

Gently fold in the mashed raspberries.

Cover and refrigerate for about two hours, or until firm enough to scoop.

Use a melon baller or spoon to scoop out portions and roll them into balls.

Roll each truffle in cocoa powder or confectioners' sugar before serving.