1½ cups fresh or frozen blackberries, thawed
2 tablespoons icing sugar
2 tablespoons lime juice
chilled sparkling wine
Put the blackberries and icing sugar in a food processor and process until smooth.
Strain the purée through a fine sieve into a bowl, discarding the pips. Stir in the lime juice.
To serve: Put 2 tablespoons of purée in each flute and top with sparkling wine.