Prosecco pairs nicely with peaches or nectarines. If you can’t find Prosecco, substitute another light sparkling wine.
Pour the Prosecco or sparkling wine into a large glass bowl. Cut the vanilla beans open lengthwise; with the back end of a knife, scrape out the seeds. Whisk the seeds and the beans into the Prosecco. Add the sliced nectarines, cover, and chill 2 hours, gently stirring the mixture once midway through chilling.
To serve, divide the nectarines among six wine- or martini glasses. Pour some of the Prosecco over the nectarines and top with a scoop of raspberry sorbet. Garnish with mint and vanilla beans.