how do i make a chocolate sponge cake

am sorry no help here I have never made one

3/4 cup cake flour 1/4 teaspoon Salt 4 tablespoons Cocoa 1 tablespoon Lemon juice 5 Eggs, separated 1 cup Sifted sugar Sift flour, salt and cocoa together. Add lemon juice to beaten egg yolks and beat with rotary egg beater until thick enough to hold a soft peak. In separate bowl, beat egg whites until stiff but not dry. Fold in sugar in small amounts, then fold in egg yolks. Fold in flour mixture in small amounts. Pour into ungreased tube pan, cut through batter with spatula to remove large air bubbles and bake in a 350 degree F oven for 45 to 60 minutes. Invert pan and let cake hang in pan until cool.

I usually guess at the ingredients when making a sponge. Grab about 250 grams of self raising flour chuck in some hot chocolate powder, stork butter, 2 eggs lots of sugar maybe some flavouring and syrup is nice. Then mix by hand for 20 minutes giving yourself little rests in between. Stick in the oven 200 degrees for 40 minutes when it has risen turn the heat off but, leave the cake in the oven for 5 minutes then take out and leave to stand for half an hour. Then it should be perfect.