600g mixed frozen berries
1 cup (220g) Chelsea Caster Sugar
1 vanilla bean, split lengthways, seeds scraped
2 tablespoons creme de cassis (optional)
2 eggwhites

Place the berries, sugar, and vanilla pod and seeds in a saucepan over low heat and stir until the sugar dissolves.
Increase the heat to medium-low and simmer for 4 minutes or until thickened slightly. Cool for 10 minutes, then stir in the creme de cassis.
Pour the mixture into a plastic container and freeze for 3 hours or until the sides begin to firm. Place the sorbet in a food processor and process to break up the ice crystals, then return to the plastic container and freeze for a further 2 hours.
Place the sorbet in a food processor with the eggwhites and process until the mixture is combined. Return the mixture to the plastic container and freeze for 3-4 hours until firm. Serve in scoops.