Sponge cake is a typical French pastry and is very easy to prepare with just a few ingredients. The dough should be as light and fluffy as possible. To do this, gently mix the ingredients together and beat the batter for 15 minutes until fluffy. Spread it on the baking tray and tap the tray a few times on the work surface so that the large air bubbles can escape and no holes or cracks appear when rolling the roulades.