2/3 cup fresh lemon juice 2/3 cup superfine sugar 1 cup vodka 1/2 cup limoncello 2 teaspoons vermouth 1 (750 ml) bottle chilled dry Champagne or sparkling wine Ice Lemon twists, for garnish
Combine the lemon juice, sugar, vodka, Limoncello, and vermouth in a large nonreactive bowl and stir until the sugar is completely dissolved. Cover and refrigerate until chilled, 1 to 2 hours. Add the Champagne and stir to combine. Serve over ice in highball glasses, garnished with lemon twists.