This is a generic sponge recipe. The quantities can be altered as long as the ratio remains the same. Flavouring is usually added, I suggest vanilla essence or cocoa powder. This sponge is ideal for "sponge sandwich" cakes, which can be made by either baking two and filling, or baking one then cutting it in half and filling. Typical fillings include jam and butter icing. Preheat oven to Gas Mark 5 / 190 degrees C / 375 degrees F. Cream the butter with the sugar until light and fluffy. Add the eggs and beat mixture until smooth. Fold in the flour. Pour into a greased tin and bake for 20-30 minutes. Turn out onto a wire rack and leave to cool.