Whisk cream with vanilla and 1 tablespoon maple syrup just until silken and very soft peaks form. In a small saucepan over medium heat, whisk together coffee, whiskey, cocoa, and remaining 1 tablespoon maple syrup. Cook until scalding and bubbles appear along edge of pan (do not let boil). Remove from heat. Whisk in 2 tablespoons cream mixture. Divide evenly between two mugs. Top with remaining cream mixture, sprinkle with cocoa, and serve immediately.