Combine cream and sugar in a small saucepan and heat until sugar dissolves. Remove from fire and cool.
Place the berries in a food processor and puree. Pass the puree through a fine sieve to remove the seeds. Add vanilla extract and stir. Pour in the cream with sugar and beat.
Pour the mixture into a container and refrigerate for at least 4 hours. Every 30 minutes. Take the container out of the refrigerator and stir the mixture with a whisk.