For the hot cocoa, whisk together the condensed milk and cocoa powder over medium heat.
Slowly whisk in the vanilla, salt and whole milk. Heat until warm, but do not boil.
Whisk in water and continue to heat over medium heat until desired temperature. DO NOT BOIL.
When ready to serve, pour cocoa in a mug with a couple dollops of whipped cream or mini marshmallows. Enjoy!
Notes
Keep your hot chocolate warm in the slow cooker on low or warm setting.
What kind of cocoa powder is best for hot chocolate? Any unsweetened cocoa powder will work. I use regular Dutch processed cocoa (the same kind I use for baking). Do not use the powders labeled "drinking chocolate" as those are usually sweetened.
Can you use evaporated milk instead of condensed milk in this cocoa? No, evaporated milk should not be used. Condensed milk contains added sugars boiled into the milk, which is necessary for this hot chocolate recipe.