These delicious treats are perfect for those who are watching their fat intake, but have cravings for cake. It's also a great way of using up any leftover egg whites you may have lying around in the fridge/freezer. A fat-free sponge cake hides a splodge of your favourite jam underneath. These cakes are also freezer friendly.
You can use up to 200g of caster sugar if you like the cakes sweeter.