Combine chocolate and water in a heavy saucepan; cook over low heat until chocolate melts, stirring frequently. Remove from heat.
Gradually stir about onefourth of chocolate mixture into egg yolks; add to remaining chocolate mixture, stirring constantly. Return to low heat; cook, stirring constantly, 1 minute or until smooth and thickened. Remove from heat; cool.
Beat 1 cup whipping cream until foamy; gradually add sugar and cinnamon, beating until soft peaks form. Spread 1 cup whipped cream mixture in bottom of meringue shell.
Gently fold chocolate mixture into remaining whipped cream mixture; spread over whipped cream layer. Chill at least 3 hours or overnight.
To serve, garnish with additional whipped cream and pecans.