In a food processor combine chocolate, sugar and cinnamon, chopping using 3 on/off turns and then finish processing until mixture is fine.
With machine running pour hot milk and vanilla through food tube and blend until chocolate is melted (10 seconds). *Can be prepared ahead to this point and refrigerated for up to 2 days, bringing to room temperature before proceeding.
With the food processor running pour cream through food tube, processing until thick.
Reheat chocolate mixture in a saucepan over medium heat, stirring frequently.