Defrost half the raspberries. Bring the rest of the frozen berries, 5-7 tablespoons of water, sugar and vanilla sugar to the boil briefly. Stir in the grappa and puree. Fold in the rest of the raspberries.
Crumble 2 meringue shells. Put other meringue shells and 1 scoop of ice cream in 8 dessert bowls or on plates. Pour hot raspberry sauce over it, sprinkle with meringue crumbs.