Glasses of sparkling wine taste peachy with a frozen fruit puree and elderflower liqueur.
Puree peaches, sugar, and lemon juice in a blender until smooth. Pass mixture through a fine sieve into a metal bowl. Freeze until firm, at least 6 hours.
Scrape granita with a fork until fluffy. Freeze until ready to use.
Fill 20 Champagne flutes halfway with Prosecco (you'll have some left over). Add 1 tablespoon liqueur to each. Top each glass with 1 tablespoon granita. Serve immediately.
Peach puree can be frozen overnight. Scraped granita can be frozen for up to 3 days. Scrape again before using.