Here's the recipe
Homemade Chocolate Milk
First you make chocolate syrup:
In a saucepan, combine 1 cup cocoa, 1 1/2 cups sugar, 1/2 tsp salt and 1 1/2 cups water. (I added a small splash of vanilla as well.) Bring to a boil and simmer for 5 minutes, stirring constantly. Store in a sealed container in the refrigerator.
To make chocolate milk, add 1 or 2 tbsp to a glass of cold milk. Or, however much you want. A large glass of milk will definitely need 3-4 tbsp. Stir and serve. Enjoy!