10 inch square sponge cake recipe help please!

[hooliodancer]

I can't find one anywhere! Does anyone have one please?
I am sure I found a website once which gave various quantities for different size tins, but I have searched and searched and can't find it.
Thanks.

For a Madeira sponge, use the following mix for every 15 square inches of cake (that will go in to a 10" x 10" 6.7 times.....so multiply up by 7 times.
1 Medium Egg
2ozs Butter
2ozs Caster Sugar
2ozs Self Raising Flour
1oz Plain Flour
Zest of half a lemon
1 tsp Lemon Juice

Gas 3 or 160 deg.C (reduce for fan assisted) for 45 - 50 minutes. As this is a large cake it would be better to use a cake cone/core to get the heat in to the middle to ensure that the middle is baked before the outside goes crusty.

Thanks so much!