My Swiss roll is very stretchy. It can stretch and bend into a roll without cracking.
The flexibility is due to the way the eggs are beaten. Egg whites are whisked to firm peak stage, then yolks are added 1 at a time and whisked thoroughly. Compared to the whole egg or chiffon method, this makes a cake that's more stretchable.
Not all cakes are flexible and stretchy. When you roll a stiff cake,