Defrost raspberries if using frozen ones. Keep 12 raspberries for decoration and purée the rest with the hand blender.
Divide the purée over 4 cocktail glasses and add a scoop of vanilla ice cream to each glass. Carefully pour in the champagne to make a separate layer on top of the raspberry purée.
Garnish with the rest of the raspberries.
5 minutes preparation time
(if using frozen raspberries, allow for extra time to defrost before preparation)