Heat 2 cups of milk in a saucepan over medium heat
Add 2 tablespoons unsweetened cocoa powder
Add 2 to 3 tablespoons sugar, to taste
Add 1/4 teaspoon vanilla extract
Add a pinch of salt
Whisk until smooth and hot
Do not let it boil
Pour into a mug
Top with whipped cream or marshmallows if desired