Add bourbon, bitters, and triple sec first. Fill rest of glass with champagne. Depending on the size up your flute, you might need to put less bourbon in. Garnish with orange twist.
Champagne Flute
Stir the whiskey, the bitters and the sugar in a collins glass until the sugar is dissolved. Fill up with champagne and garnish with a slice of peach.
Collins Glass
Stir all ingredients (except champagne) in a mixing glass filled with ice cubes. Strain into a champagne flute, fill with champagne, and serve.
Champagne Flute