How to make
The sponge cake products are mixed by adding cocoa to 1/3 of the sponge cake mixture, it is stirred and mixed with the other part in the mold, by stirring lightly with a stick.
The resulting sponge cake mixture is poured into a mold - diameter 10″ (25 cm), height 4″ (10 cm).
Bake the marble sponge cake at 340°F (170°C) in a preheated oven - on the first rack from the bottom up, until it is fully baked!
A very successful sponge cake with sparkling water was obtained.