In a small saucepan, whisk the sugar, cocoa powder, and salt. Whisk in the hot water until smooth. Add the milk and stir until well combined.
Heat the mixture over medium-high heat, stirring, until hot.
Divide into mugs and top according to your preferences.
Notes
Store any leftovers in a covered container in the refrigerator. Reheat before serving.Optional toppings and garnishes include: marshmallows, whipped cream, ground cinnamon, cinnamon sticks, chocolate syrup, chocolate shavings, chocolate sprinkles, peppermint sticks, crushed peppermint candiesTo make this vegan: Use a plant-based milk and be sure to use cane sugar that is vegan-certified.