...or Classic Cocoa, depending on your location. Mom always made this for us kids as we were growing up, but it was always a bit powdery. Of all people, my brother, Jake, came home from a cooking class & told us about making the paste, then adding the milk. No more powder! Now why didn't I think of that...? =^..^=
Mix cocoa powder, sugar, and salt in a saucepan with a large spoon.
Add about 3 Tablespoons of the milk to the dry ingredients.
Stir well to make a smooth paste.
Gradually whisk in remaining milk while cooking over low-medium heat. Do NOT boil. Stir often.
When the hot chocolate is at the desired temperature, pour into mugs. Top with marshmallows or whipped cream. A candy cane makes a tasty stirrer.
In a rush? Here's a shortcut. Mix up the cocoa as directed above, but in a microwave-safe measuring cup or bowl. Microwave for about 5 minutes TOTAL, stirring every 2 minutes, then checking during the final time to make sure cocoa is hot but not boiling.