This classic Italian sponge cake or 'Pan di Spagna' is made without butter and doesn't contain any raising agent. Instead, eggs are whipped until very light and fluffy to make this light and airy cake. Take the eggs out of the fridge at least 1 hour before starting to make this cake. If cold, they won't whip as expected.
For a softer and taller cake, use 120g plain flour and 60g potato flour.