Put pears and 3/4 cup sparkling wine in a medium pan over medium-high heat. Bring to a boil, then lower heat to maintain a steady simmer. Cook, stirring occasionally, until pears are tender, about 10 minutes. Whirl pear mixture and sugar in a blender until smooth. Stir in corn syrup, cover, and chill.
When mixture is cold, stir in remaining 3/4 cup sparkling wine and freeze in an ice cream maker according to manufacturer's instructions.
Serve immediately, or transfer to a freezer-safe container, cover, and freeze until ready to serve.
