Puree the remaining cherries then add to a small saucepan with the cherry juice and sugar. Bring to the boil then simmer for about 4 minutes. Remove it from the heat and let cool completely.
Whisk the cream and vanilla until stiff. Divide the cream in half. In one half add half the cherry mixture and combine.
In the base of the serving mold, create a layer of plain cream.
Over the top of the plain cream add the cherry cream.
Cover and freeze for at least 3 hours, preferably overnight. Remove from the freezer a few minutes before serving. Invert the parfaits onto the serving plate then drizzle with the remaining sour cherry sauce.