1 cup Chelsea White Sugar
1 cup water
5 cups mulberries or blackberries
1/4 cup cassis, elderberry or blackberry liqueur, or Port

If you are using mulberries, pick off all the green stems from the berries.
Bring the Chelsea White Sugar and water to a boil over medium heat. Let it simmer gently for 3-4 minutes. Turn off the heat and let it cool a bit.
Meanwhile, put the berries in a blender. Pour the syrup over them while it is warm but not hot. Buzz into a puree.
Push the berries through a fine-meshed sieve set over a bowl using a rubber spatula or wooden spoon; this removes a lot of the seeds and stems.
Pour the liquor into the bowl with the pureed berries and chill in the fridge for an hour or so.
Pour into your ice cream maker and follow its directions.