St. Germain Cocktail

Bahan-bahan (1 porsi)

• 1 1/2 ounces dry gin (such as Hendrick's or Tanqueray, or vodka)
• 1 ounce St. Germain liqueur
• 3/4 ounce freshly squeezed lemon juice
• 3 ounces brut champagne (or prosecco, or other dry sparkling wine)
• Lemon twist or peel (for serving)
• Ice (for cocktail shaker)