1. To prepare the whipped cream, put the cream in a large mixing bowl. Using a whisk or an electric mixer, whip the cream until it begins to stiffen. In a small bowl, mix the sugar and cinnamon together and add to the cream. Continue whipping until soft peaks form. If not serving immediately, cover and refrigerate up to 3 hours ahead of time.

2. To prepare the hot chocolate: In a large saucepan, combine the milk, cocoa powder, sugar, and vanilla and cook, stirring constantly, until the mixture is hot, about 5 minutes.

3. Add the chocolate and cook, stirring constantly, until it has melted completely. Remove from the heat and pour into large cups. Top with cinnamon whipped cream and serve at once.