set the oven to 160°C on the thermo function (180°C on the top-down function).
whip egg whites to stiff foam. While still whisking with a mixer, add sugar and mix until the mixture becomes thick and glossy. Then add egg yolks and continue to mix with a mixer to a light, creamy mass.
Add oil to the egg mixture and mix gently with a spatula
mix flour with cocoa, baking powder and sift on top of the egg mixture, mix with a spatula.
transfer the dough to a 25x30cm baking pan lined with baking paper. Level out and put into the preheated oven. Bake for about 25-30 minutes. After removing from the oven, set aside to cool completely.
Remove the cooled sponge cake carefully from the tin, remove the baking paper (put the paper back in the tin), cut off the baked crust from the top (see FILM). Cut the sponge cake horizontally into two parts. Put one part of the sponge cake back into the tin.
mix the ingredients for soaking and drizzle half of the punch over the sponge cake in the tin.