Preheat the oven at 180 degrees Celsius.
Spread the margarine on the bottom and edges on a baking form with removable edges. Spread the bread crumbles evenly in the form.
With an electrical mixer whip the sugar and the eggs together so it becomes white and fluffy.
While stirring add the potato flour, baking powder, and the gluten free flour.
Pour it in the baking form, and place it on the lower part of the oven for 40 minutes.
Take out the cake and let it become cold, then divide it in 3 layers.
If you use powder vanilla cream prepare it according to the instructions on the box. If you use bought one from the store you don't need to prepare it.
With an electrical mixer whip the whipping cream and the vanilla sugar in to a hard foam, it should resembles shaving cream in the consistence.
Grate the white chocolate in thin slices.
Mix 2/3 of the blueberries together with 1/3 of the vanilla cream, ½ of the white chocolate, and ½ of the whip cream.
In another bowl mix 2/3 of the vanilla cream and ¼ of the whip cream together.
In another bowl mix ¼ of the whip cream and ½ of the chocolate together.
Place the bottom layer of the cake on a plate and spread evenly the vanilla and whip cream mixture on top.
Place the middle layer of the cake on top and spread evenly the mixture with blueberries, vanilla cream, whip cream and chocolate evenly on it.
Place the top layer on top and spread evenly the mixture with the whip cream and chocolate on it.
Place the marzipan lid on top and decorate with the rest of the blueberries.