To make our No-Cook Simple Syrup, combine 2 cups each superfine sugar and water in an airtight container. Cover and shake until sugar dissolves. Makes 3 cups.
Stir gin, No-Cook Simple Syrup, and fresh lemon juice with ice in a medium pitcher for 10 seconds. Strain into Champagne flutes or coupe glasses.
Top with chilled Champagne (Prosecco or other sparkling wine works in a pinch). Garnish with lemon twists.