In a medium saucepan, whisk together cocoa powder, sugar, and salt.

Gradually add the milk while whisking to combine with the cocoa mixture.

Place the saucepan over medium heat and cook, stirring occasionally, until the mixture is hot but not boiling, about 8 minutes.

Stir in the heavy cream and vanilla extract. Heat for an additional 1-2 minutes.

Remove from heat and pour into mugs. Top with whipped cream and chocolate shavings if desired.