Here i give you a basic recipe for sponge cake with variations.
Ingredients for the sponge
1 cup sugar(100 gm)
1 tsp.cornflour / custard powder
1 cup flour
1/2 cup warm milk / 1/2 cup hot water
1 tsp.baking powder
1/2 tsp.lime juice or white vinegar or curd
1 cup nuts(optional)
a pinch of salt
1/4 tsp.vanilla essence
Separate the whites and the yolks.Beat the egg yolks with half of the sugar until creamy and set aside.Beat the egg whites with a pinch of salt,until peaks form,then add in remaining sugar gradually and beat.Add the egg yolk mixture and beat.Sift flour with the baking powder.and add all other ingredients gradually,beginning with flour and ending with flour.Fold in nuts if using.Blend evenly.Pour into a pan(greased only at the bottom of the pan),and bake in a moderate oven for 30-40 mins.
Note:When you bake a sponge cake,always preheat the oven to 180 degrees and bake in this heat for half the time needed for baking and then lower the heat to 160 degrees.Remember not to remove the cake immediately from the oven once done.Switch off and allow to be in the oven for at least 10 mins otherwise the cake will sink in when cool.The sides of the pan are not greased as it will prevent the cake from rising.
Chocolate sponge:Replace the cornflour with cocoa powder,and the milk with hot water/or half milk and half water.Mix the cocoa powder with the hot water and use.
Coffee sponge:Same method as for chocolate replacing cocoa with instant coffee powder.
Mocha sponge:Mix in hot water the coffee powder and cocoa powder(1/2 tsp coffee+1/2 tsp cocoa)
Likewise you can open up to your creativity and use fruit pulp replacing half the amount of hot water.
This sponge is good for icing cakes,gateaus,fruit trifles, swiss rolls, cup cakes and even made plain with or without nuts.
You can use this coffee sponge mixture and make tiramisu too.(pour into finger shaped moulds or cut into pieces ).