500 grams mixed berries, frozen can be used
150 ml water
150 grams caster sugar
200 ml water
juice of 1 large lime
1 egg white
fresh raspberries to garnish
Put the berries and water in a saucepan and bring to the boil. Cool a little then purée until smooth and press through a sieve into a bowl.
Put the sugar, water and lime juice in a saucepan and dissolve over a medium heat. Bring to the boil then cook until the syrup reaches soft ball stage (115°C on a sugar thermometer). To test without a thermometer, drop a teaspoonful into a glass of cold water. You should be able to roll it into a ball. Set aside to cool.
Combine the two mixtures, pour into a shallow freezer-proof container and freeze until just set.
Put the sorbet and the egg white in a food processor and blend until smooth. Tip back into the container and freeze until firm. The egg white gives the finished sorbet a smoother texture than one made without.
To serve: Place scoops of sorbet in chilled glasses. Pour over chilled champagne and garnish with fresh raspberries.