In a large bowl, sprinkle the pepper all over the sorbet and fold it in with a rubber spatula. Cover and freeze for about 3 hours, until firm.
Chill 8 champagne saucers. Using a 1/2-ounce ice cream scoop, place 3 scoops of sorbet in each saucer. Pour about 1/3 cup of Prosecco into each saucer.