Does your 铲子 has sharp edges? Sharp edges break air pocket.|
I just remember I first mix the dry ingredients into the egg yolk mixture . . . then mix a little of whipped egg white into the mixture till it is "fluid", then FOLD them into egg white CAREFULLY and slowly. Almost like 画圈的搅拌 but much slower and careful - if your utensil leave the mixture, it is said that it break air pockets again. The steps or sequence is not really that important, the key is not to break the air pockets in the egg white.
蛋糕分层 could be due to insufficient mixing, yes u can break the air pockets without proper mixing.
Sorry, haven't make this thing for too long! As I have mentioned it is the easiest and the hardest receipe. Hope someone who is studying cooking will continue to help u out, as they may be better describe the procedures.