Divide the eggs into proteins and yolks, beat the proteins with half the sugar until stable peaks.
Whisk the yolks with the rest of the sugar and beat until foam. Mix them with proteins.
Add sifted cocoa flour to the egg mass. Mix until smooth and pour the finished dough into a greased form.
Bake chocolate sponge cake at 180 degrees 35 minutes, check readiness with a toothpick.
Chocolate sponge cake is ready, cut the cake in half and brush with your favorite cream.