Place the strawberries and icing sugar in a blender or food processor and blend or process until mixture forms smooth puree.
Pass the puree through a fine sieve into a bowl and discard the seeds in the sieve. Cover the puree with plastic wrap and chill in the refrigerator.
Half-fill 8 champagne flutes with the crushed ice, if using. Divide the chilled strawberry puree among the flutes, then top each with 1 tablespoon vodka. Top up with the sparkling wine.
