Hot Chocolate

Comments
This is from a 100 year-old recipe shared on How To Cook That.
Here is that recipe as written in the cookbook:
Choice Recipes by Miss Maria Parloa specifically prepared for Walter Baker & Co Ltd.
PLAIN CHOCOLATE
For six people, use one quart of milk, two ounces of Walter Baker & Co.’s Premium No.1 Chocolate, one tablespoonful of cornstarch, three tablespoonfuls of sugar, and two tablespoonfuls of hot water.
Mix the cornstarch with one gill of the milk. Put the remainder of the milk on to heat in the double-boiler. When the milk comes to the boiling point, stir in the cornstarch and cook for ten minutes. Have the chocolate cut in fine bits, and put in a small, iron or granite-ware pan; add the sugar and water, and place the pan over a hot fire. Stir constantly until the mixture is smooth and glossy. Add this to the hot milk, and beat the mixture with a whisk until it is frothy. Or, the chocolate may be poured back and forth from they boiler to pitcher, holding high the vessel from which you pour. This will give a thick froth. Serve at once.
Ingredients
1 qt. milk
2 oz. premium dark chocolate**
1 Tbsp. cornstarch 3 Tbsp. sugar
2 Tbsp. hot water.  
** Look for a dark chocolate with the highest % of cocoa solids. Or, as stated in the original recipe, Walter Baker & Co.’s Premium No.1 Chocolate.


Directions
Mix the cornstarch with about 8 Tbsp. of the milk.
Put the remainder of the milk on to heat in a really big pot.
When the milk comes to the boiling point, stir in the cornstarch and cook for ten minutes. Ten minutes is important to get the cornstarch to cook and some of the water in the milk to evaporate.
Have the chocolate cut in fine bits, and put in a microwaveable dish.
Add the sugar and water
Microwave intermittently until melted.
Stir constantly until the mixture is smooth and glossy. It is okay if there are sugar grains in it.
Add this to the hot milk.
Top with marshmallows, whipped cream, shaved chocolate, or all three!
Serve at once.

For six people