Using a separate bowl (this will have to be quite large), beat the egg. To make your cakes extra fluffy keep beating it even if you think it is done. The perfect outcome would be to end up with a "blob" of "froth" but that is not an easy feat. Then, spoon around a quarter of the egg to the beaten fat and beat it in thoroughly. To achieve best results make a well for the egg and when first starting to beat it in, mix the mixtures together like you would cement. After that, pour the mix into the rest of the egg and again, beat thoroughly. if you are adding an extract to this recipe then now is the time to do it, beating into the mix.