Combine 1/2 cup cream and cinnamon in small saucepan; bring to low boil. Remove from heat. Add chocolate and whisk until melted. With spatula, transfer chocolate mixture to large bowl. In another large bowl and using electric mixer, beat remaining 2 cups cream until soft peaks form. Gently fold 1/4 of whipped cream into lukewarm chocolate mixture. Fold remaining whipped cream into chocolate mixture in 3 additions, just until incorporated. Divide mousse among 8 glasses or bowls. Chill until set, about 3 hours. Can be made a day ahead, just cover tightly and keep chilled. Serves 8.