Put the coconut milk in a medium pan, add the chocolate, cocoa powder, sugar, cinnamon powder and vanilla extract. Place the pan on a medium heat and mix all the ingredients until the chocolate is starting to melt.
Bring the mixture almost to boil and turn off the heat.
Separately, whip the cream until it forms soft peaks.
For serving, pour the hot chocolate into mugs or glasses, add a generous amount of whipped cream and marshmallows.
Serve hot.