Beat eggs with salt on high speed for 7 minutes.
Add sugar slowly and keep mixing.
Add oil and vanilla sugar.
Continue mixing.
In a separate bowl, combine baking powder and flour.
Add flour mixture to batter and mix with wooden spoon slowly.
Add currants to mixture.
Sift in cocoa powder, fold batter 3 to 4 times to get marble effect.
Pour into greased pan.
Sprinkle with almond slivers or walnut if desired.
Bake 365F for 30 minutes.
Cut when cooled. Sprinkle powder sugar over top.