1. Place the bar of dark chocolate and ¼ cup of the heavy cream in a bowl.
2. Allow that to sit for 5 minutes, then add the rest of the heavy cream and cocoa powder.
3. Sift in the powdered sugar, then use a whisk or electric mixer on low to combine the ingredients.
4. Next, add the vanilla extract and salt.
5. Stir to combine, then pour in 3 glasses and refrigerate overnight.
6. Top with whipped cream and chocolate shavings, then enjoy!