For hot cocoa mix: Combine all of the ingredients in a large bowl. Working in two batches, pulse the ingredients in a food processor until the hot chocolate in finely ground.
For whipped cream: Place you mixing bowl and whip in the freezer fo 15 to 20 minutes.
Pour the cream into the cold bowl and whip cream until stiff peaks are just about to form. Beat in vanilla and sugar until peaks form. Make sure not to over-beat, cream will then become lumpy and butter-like.
To make hot cocoa: Heat four cups milk on medium low heat until almost boiling. Be careful not to burn the milk. Stir 1 1/3 cups of of the cocoa powder into the hot milk.
Serve with whipped cream and marshmellows.
This make around 6 cups of cocoa powder.
*Whole milk works the best, but both 2% and skim would also work. It will not be as creamy though. *For every 1 cup of milk add 1/3 cup cocoa powder (or more) to your taste.