A champagne cocktail is an alcoholic cocktail made with sugar, Angostura bitters, Champagne, brandy and a maraschino cherry as a garnish. A recipe for the cocktail appears as early as "Professor" Jerry Thomas' Bon Vivant's Companion (1862), which omits the brandy or cognac and is considered to be the "classic" American version. It is also one of the IBA official cocktails.
Add dash of Angostura bitter onto sugar cube and drop it into champagne flute.
Add cognac followed by gently pouring chilled champagne.
Garnish with orange slice and maraschino cherry.