Combine boiling water and chopped dark chocolate in medium saucepan, stirring until chocolate melts. Add milk, coffee, cocoa powder and brown sugar. Cook over medium-low heat, stirring with a whisk. Heat five minutes or until tiny bubbles form around edge of pan. Add in Chambord and remove from stove. Pour one cup mixture into each of four mugs. Spoon one tablespoon whipped cream over each serving. Dust with cocoa powder and enjoy.