Melt chocolate in a bowl over a double boiler, stirring constantly
Once chocolate is completely melted, add in cocoa powder and powdered sugar, whisk until completely combined
Add in 1 1/2 cups of milk to chocolate mixture and whisk until smooth
Remove the chocolate mixture from the heat and allow it to cool completely
Add Ice, the remaining 1 1/2 cups of milk and chocolate mixture into a blender and blend to remove all chunks of ice and it becomes very frothy Pour frozen hot chocolate into a glass or mug and top with fresh whipped cream, toasted marshmallows and graham cracker crumbs