Combine the heavy cream, sugar, vanilla, and salt in a small sauce pan. Place the pan over medium-high heat and bring to a boil.
As soon as the heavy cream comes to a boil remove the pan from the heat and add the chocolate. Let the pan sit, untouched, for 3 minutes. Then, using a whisk, stir the chocolate and cream until fully combined.
Pour the ganache into a dish to cool. Press a piece of plastic wrap directly onto the surface of the ganache as it cools to prevent a skin from forming on the top.
When the ganache is cooled, move it to the refrigerator and let it cool further, until firm.
When the ganache is firm, scoop out tablespoons and roll them into balls with your hands. Then, roll the balls in cocoa powder.