In a blender, blend frozen coffee or ice cubes, milk, chocolate, cinnamon and sugar.
Beat very well until it forms a "foam" and set aside.
For decoration, melt the semisweet chocolate in a bain-marie or microwave. Then, whip the whipped cream of your choice.
First place the melted chocolate around the clear mug (if you have one). Place the beaten chocolate-coffee, the whipped cream and finally a little more chocolate on top. It's a delight!