Put the crème de cassis or cordial in a saucepan over a low heat and gently heat, then add the berries. Stir, cover and cook for about 5 minutes or until the fruit has thawed and is beginning to collapse. Remove from the heat and cool completely.
Process most of the berry mixture with the fromage frais and milk in a food processor or blender until smooth.
Scrape in the seeds from the vanilla pod and beat to combine.
Fold the reserved berries into the fromage frais mixture until just combined. Spoon into 4 glasses and serve immediately, decorated with toasted almonds.