Combine milk, sugar and cocoa powder in a saucepan and heat it up on medium heat, until you see some tiny bubbles on the edges and it's steaming a little bit.
Bring the heat to medium low, add chopped dark chocolates, cinnamon, nutmeg, salt and stir for about a minute until all the chocolate pieces are melted and it's nice and creamy. Taste the hot chocolate, you can add more sugar or spices based on your taste.
Take it off the heat, add vanilla extract and stir. Top with whipped cream or marshmallows if desired, and sprinkle some cocoa powder on top to make it extra fancy! Enjoy!