Mix eggs, caster sugar, sunflower oil, milk, flour and baking powder in a large bowl and pour the resulting mixture into greased and flour dusted deep tray (20x30x5cm) and place into preheated oven 180 C / Gas 4 for about 30-40 minutes.
Grate pealed and deseeded apples to get approximately 1 litre of finely grated apples. Mix apples, blancmange powder and raisins in large saucepan and heat until the mixture has a thicker consistency. You can also add some sugar if the apples are very sour. Leave outside until the mixture cools to room temperature, then add the soured cream and mix thouroughly.
Spread the apple mixture on the baked dough and cover with well whipped whipping cream. Serve chillled.