In a small saucepan, combine cocoa powder, sugar, and salt.
Add 2 tablespoons of milk to the dry ingredients and stir to create a paste.
Gradually add the remaining milk, stirring continuously.
Heat the mixture over medium heat, stirring occasionally.
Once the cocoa is steaming but not boiling, remove from heat.
Stir in the vanilla extract.
Taste and adjust sweetness if necessary.
Pour the hot cocoa into mugs.
Top with whipped cream.
Garnish with chocolate shavings or a sprinkle of cocoa powder.