For the checkerboard cake, beat eggs, powdered sugar and vanilla sugar until foamy. Add oil and rum. Mix flour, baking powder and cocoa powder and fold in. Bake at 180 °C (top and bottom heat) for approx. 40 minutes. Allow to cool.
For the cream, mix curd, fine crystal sugar, lemon juice and rum. Prepare gelatine as described on the package and stir into the cream. Whip the cream and fold it in.
Cut the cake in two. The middle piece should be slightly thicker. Cut four circles from the middle piece. Place bottom layer in a cake pan and spread a little of the cream on top.
Then place two circles on top and fill the spaces with the cream. Then place the other two circles on top and again fill the spaces with cream.
If there is still some cream, spread it on top and place the top cake layer on top. Whip the cream with cream stiffener and spread it on the cake. Sprinkle cocoa powder over the cake.