In a coffeemaker basket, combine the coffee and ground cinnamon. Prepare 4 cups brewed coffee according to manufacturer's directions., Meanwhile, combine the milk, sugar, cocoa and vanilla in a saucepan. Cook over medium-low heat for 5-7 minutes or until small bubbles appear on the sides of the pan, stirring occasionally (do not boil). Pour hot milk mixture into four coffee cups, then add cinnamon-flavored coffee. Garnish with cinnamon sticks and whipped cream if desired.