Melt chocolate bar pieces (or chocolate chips) on medium heat in a medium saucepan. Whisk continuously until melted.
When chocolate is melted, add 1 cup milk and 1/2 cup chicken broth, slowly stirring so the chocolate begins to dissolve. It won't dissolve fully until the liquid is hot.
Add cacao powder, maple syrup, cinnamon, salt, and vanilla. Stir/whisk ingredients on medium heat until steaming, but not quite boiling. Most of the cacao powder should be dissolved at this point.
Pour cocoa into a mug through a mesh strainer to catch any bits that did not dissolve. This is not a necessary step, but I highly recommend because it makes the cocoa extra smooth. Otherwise it can be a touch grainy.
Snuggle up and enjoy!