Chocolate Sponge Cake

Method

1. Preheat the oven to 160°C (static) or 150°C (fan).
2. Butter and flour a 24 cm round cake pan, tapping out excess flour.
3. Sift together the flour and cocoa powder and set aside.
4. In a large bowl (or stand mixer bowl), crack the eggs one at a time, checking for shell pieces.
5. Add the sugar and a pinch of salt to the eggs.
6. Beat the eggs and sugar with a whisk (or stand mixer with whisk attachment) for exactly 20 minutes, until pale, thick, and tripled in volume.
7. After 20 minutes, add the vanilla essence and beat for another 15-20 seconds.
8. Sift one-third of the flour-cocoa mixture over the egg mixture and fold gently from bottom to top with a spatula until just combined.
9. Sift and fold in the second third of the flour-cocoa mixture, again folding gently and briefly.
10. Sift and fold in the remaining third of the flour-cocoa mixture, folding just until no dry streaks remain. The batter should be smooth and airy.
11. Pour the batter into the prepared pan. Do not tap or shake the pan to level it, as this will deflate the air bubbles.
12. Bake for 35-45 minutes (fan-assisted: 35-40 minutes; static: 40-45 minutes) or until the cake pulls away from the sides of the pan.
13. Remove from the oven, cover the pan with a lid or plastic wrap to retain moisture, and let it cool completely.
14. Once cool, the cake can be stored covered in the refrigerator for up to a day before filling or frosting.