Combine 8 cups water and cinnamon in large saucepan bring to a boil. Place remaining water and flour in blender container cover. Blend until smooth. Pour mixture through fine mesh sieve into cinnamon water mixture. Bring to a boil. Reduce heat to low; cook, stirring constantly with wire whisk, for 6 to 7 minutes or until mixture is thickened. Stir in sugar, chocolate and vanilla extract. Cook, stirring frequently, for 4 to 5 minutes or until chocolate is melted and flavors are blended very well. (You can use milk instead of water if you want)