The Champagne Cocktail is classically made using cognac, though any brandy can work just as well here. This recipe uses a cherry brandy because we find this drink to be a good vessel for American or fruit brandies, and also because it seems a sensible pairing with the maraschino cherry that garnishes the drink.
One may wonder why a sugar cube is employed in this beverage (rather than a measure of demerara syrup, which would dissolve much more easily). Its presence is purely aesthetic; the rough surface of the cube offers an easy place for bubbles to form, leading the drink to visibly "sparkle". The cube offers almost no sweetening function and - consequently - the cocktail itself is quite dry.