Place one or two sugar cubes in the bottom of a champagne flute.
Add a few drops or dashes of bitters.
Top with brandy, then top with with champagne. Serve immediately.
Notes
Make it non-alcoholic: Use a non-alcoholic spirit such as Ritual gin alternative or Ritual whiskey alternative instead of the brandy. Substitute ginger ale, sparkling lemonade or sparkling cider instead of champagne. Substitute the brandy: You can make this recipe with other spirits. Vodka is a common swap for brandy. Gin or bourbon also work. Use flavored bitters: Try using a flavored bitters, such as orange bitters or ginger bitters, instead of classic Angostura to give the cocktail subtle new flavors.