I arranged my fluffy and soft plain sponge cake to make this chocolate sponge. I added honey and starch syrup, and adjusted the amount of fat so as to make a fluffy and moist, but not dry sponge cake.
You have to beat the eggs well, but do not beat too much. After that, the texture must be made fine with a hand mixer at a lower-speed. Fold in the mixture using a spatula with a cutting motion and rotate your bowl against the direction of the spatula. Do not over-mix but make sure the cocoa liquid is combined evenly. After mixing, the volume of the batter may drop, but do not worry. When it bakes, it will rise.