What is added to a Champagne glass for a Champagne Cocktail?

In a Champagne Cocktail, the addition of a sugar cube is a classic component that not only provides sweetness but also enhances the overall flavor profile of the drink. The sugar cube is typically soaked in aromatic bitters before being placed at the bottom of the glass. Once the Champagne is poured over the sugar cube, it creates a delightful fizz and a subtle sweetness that complements the effervescence of the sparkling wine.

Other options, such as salt, fruit puree, and olive brine, do not align with the traditional recipe for a Champagne Cocktail. While salt is often used in savory cocktails, it doesn't belong in this particular drink. Fruit purees might be found in cocktails that require a different base flavor, and olive brine is characteristic of savory cocktails like dirty martinis, not a refreshing sparkling beverage like a Champagne Cocktail. Therefore, the sugar cube remains the essential ingredient that defines this classic drink.