In a saucepan, combine sugar, cocoa, and salt.
Add water and bring to a boil. Cook and stir for 2 minutes.
Reduce heat and stir in milk. Warm over medium heat but don't boil.
Remove from the heat and stir in vanilla extract. Whisk until frothy.
Place a piece of peppermint bark in the bottom of a mug.
Pour hot chocolate over bark.
Garnish with whipped cream and chopped peppermint bark. Serve immediately.