Heat the sugar and water in the saucepan until the sugar is dissolved. Add the berries and, if you have frozen goods, let them heat up completely; if you have fresh goods, simmer them gently until the berries are soft.
Pass through a sieve so that the kernels are no longer contained in the mass.
Let cool down.
Beat the egg white together with a pinch of salt until very stiff.
When the berry mixture has cooled down, lime juice and zest as well as cassis or granadine are added. Now vigorously fold in the egg white until a homogeneous mass is formed.
Pour into the ice cream maker, it takes about 35 - 45 minutes for the creamy sorbet to be ready.
For serving, it should be put in pre-chilled glasses or bowls. If you like, you can top it up with sparkling wine.