

For thousands of years, drinking chocolate was the only way to consume chocolate. And it was dark chocolate, too. No milk. We now think of chocolate as something to eat, but drinking our chocolate is still extremely popular.
What does it really mean to drink dark chocolate? If you start with dark chocolate, but then add it to milk, do you still have dark chocolate? Well, I enjoy a good hot chocolate milk drink as much as the next guy, so I'll leave this question unanswered. Many of the products contain cream or milk. Check the ingredients. If there is no cream or milk, and if you use water, then we can at least say that your drink is not milk chocolate.
Already Made
A few manufacturers have already done all the work for you. Pour the chocolate, heat it up, and you're done. You can probably find "chocolate milk" at your grocery store on one end, and you can find already made dark chocolate drink from bigger name chocolate makers, such as Celaya Hot Chocolate by Valrhona.
Add Pre-Mixed Powder to Liquid
This is the way most of us are probably used to making our own chocolate drink: by adding the contents of an individual serving size packet, or by spooning a measured amount of pre-mixed powder into hot liquid, usually milk or water. My wife likes to add pre-mixed powder to her coffee.
Here are a few of your options for pre-mixed powders:
These have an extra ingredient:
Melt Dark Chocolate in Liquid
One form you may see for melting dark chocolate into a liquid is the "melting stick", which generally has a single serving in solid form on the end of a stick. Stir the solid chocolate around in the hot liquid with the stick until the chocolate is melted, and the drink is ready. Some examples:
Some dark chocolate bars are made to be broken up and melted in your hot drink. Or sometimes this kind of dark chocolate comes in chocolate chip or flake form. Often these forms of dark chocolate can also be used in baking.
Add Cocoa and Other Ingredients to Liquid
If you start by adding one of these to your hot liquid, you'll need something more. Minimally, you'll need a sweetener, like sugar. This form of dark chocolate is also often used in baking.