In a small bowl combine the hot water and the cocoa powder, stir until smooth.
In the base of the slow cooker, add the chocolate, condensed milk, cinnamon stick, cinnamon powder, nutmeg, chili powder, whole milk, along with the cocoa powder mixture. Heat on low for 2 hours, stirring every 40 minutes or so.
Serve warm with marshmallows, whipped cream.
If u do not have slow cooker , put everything in a thick bottom pan and put on low flame for same time and stir it after every 20-25 minutes and so on..