“ If Takumi is beating the eggs whole, that means he's making a Genoise sponge cake for the cake layer, which has a soft and smooth texture but tends to be flat.
But by beating the eggs separated, Mimasaka is probably making a biscuit sponge cake for the cake layer, which is fluffier and will soak up more of the syrup!
"In other words, my cake layer will take better advantage of the sweet syrup than yours. I bet you picked Genoise sponge cake for its tender, smooth texture.
That's fine on its own, but if you try them side by side...
... mine will taste better.”