Bubbles instantly add festivity to any drink, and grapefruit and mint keep things summery and fresh.
In a cocktail shaker, using a muddler or the handle of a wooden spoon, muddle the mint leaves. Add the grapefruit juice, gin, and simple syrup. Fill the shaker with ice; shake well. Strain into 2 Collins glasses filled with ice. Add the Champagne; stir gently. Garnish each glass with a mint sprig and a grapefruit twist.