FOR each serving: Add 5 oz. prepared CRYSTAL LIGHT, 1-1/2 oz. gin, 1/2 oz. lime juice, 1 of the tarragon sprigs and 1 cup ice cubes to cocktail shaker; cover with lid. Shake until blended.
STRAIN and pour over additional ice into glass. Add 1-1/2 oz. champagne. Garnish with 1 remaining tarragon sprig.