Defrost the puff pastry. Preheat the oven (fan oven: 200 °C). Place puff pastry sheets on top of each other, roll out very thinly on icing sugar and roll up. Cut the roll of dough into slices about 1 cm thick so that they look like snails.
Roll out again very thin. Bake in a hot oven for 2-3 minutes until golden brown and crispy.
For the white mousse, soak gelatine in cold water. Beat the eggs and egg yolks with sugar in a hot water bath until foamy. Squeeze the gelatine and dissolve in the hot cream over a very low heat.
Chill until the cream begins to gel. Whip 500 g cream until stiff and fold into the cream. Pour some mousse half full into four glasses, cover and freeze for about 1 hour. Pour the rest of the mousse into a flat bowl, cover and place in the fridge for about 2 hours.
For the plum cream, chop the plums very finely and mix with the plum puree. Whip 100 g cream until stiff and fold it into one half of the plum mixture. Take out the glasses and spread the plum cream on top.
Put 1 puff pastry cracker in each.
Remove the white mousse from the fridge, cut off some cams or balls. Arrange on four plates with the remaining plum jam and puff pastry crackers.