Puree the berries in the container of a
food processor and strain to remove the seeds; you should have about 4
cups of puree. Heat the sugar, water, and salt in a saucepan over medium
heat until the sugar is dissolved. Stir into the berry puree and
refrigerate until cold. Stir in the lemon juice and cassis or kirsch.
Freeze in an ice cream maker according to the manufacturer's
instructions.