Blend the blackberries in a food processor until smooth. Spoon a third of the purée into a serving glass
Whisk the double cream and vanilla seeds until soft peaks form when the whisk is removed.
Fold in the yoghurt and honey. Gently fold in the remaining blackberry purée to create a 'ripple' effect.
Spoon the cream mixture into the serving glass, top with the blackberries and sprinkle over icing sugar.