In a medium bowl, mix the cornstarch and cocoa powder with 1/2 cup of the milk.
Pour the rest of the milk and the sugar into a medium saucepan and cook over medium heat while stirring until there are bubbles on the sides of the pan.
Remove from the heat and add the chopped chocolate.
Stir until the chocolate has melted, then pour in the cornstarch mixture.
Return to heat and cook over low heat, constantly stirring until the mixture has thickened and coats the back of a spoon without dripping.
Remove from the heat and pour the hot mixture into the serving dishes.
Top each dish with plastic wrap over the surface of the pudding and chill to set, about two hours.
Make The Heavy Cream
Whip the cold milk and powdered sugar in a large bowl until stiff peaks form.
Using a piping bag or a spoon, top the pudding with the whipped cream.
Notes
This recipe makes about 3 1/2 cups, enough for 4-6 servings of individual serving dishes or one large bowl.
Cover and store leftover pudding in the fridge for up to 3 days.
Room-temperature milk combines with the dry ingredients more easily, but cold milk also works.
Use chocolate bars rather than chocolate chips for this recipe, as they yield better results.
When cooking the pudding, be sure to stay close and stir continuously; it’s ready when thick enough to coat the back of a spoon without dripping.
If the mixture isn’t completely smooth and you notice lumps, transfer it to a food processor and blend briefly until smooth.
Wait until the pudding is fully chilled and set before adding the whipped cream topping.