For the cake base, brush a cake plate with some oil. Place the rim of a springform pan (26 cm Ø) on top. Melt butter. Put all cookies into a freezer bag, close the bag.
Finely crumble the biscuits with a rolling pin. Mix well with melted butter and oat flakes. Pour into the rim of the mould and press down as a cake base. Put them in a cold place.
For the creamy berries, up to 1 handful for decorating, sort and wash. Strip the currants from the panicles. Mix cream cheese, sugar, vanilla sugar and lemon juice briefly.
Whip the cream until stiff, allowing the cream firmer to trickle in. Fold cream first, then the prepared berries into the cream cheese mixture. Spread on the base. Chill for about 2 hours.
The remaining berries are sorted and washed. Decorate the cake with them.