Chocolate Sponge Cake

Line the bottom with parchment paper and lightly grease the rim so the sponge releases more easily later.

If you only have one type of cocoa, use the same total amount of cocoa and adjust the sugar to taste.

The airier the egg mixture, the lighter the sponge—best to use an electric mixer on high speed.

Do not overmix, otherwise the batter will lose volume and the sponge will become denser.

Tap the pan lightly on the work surface 1–2 times so that large air bubbles rise to the top.

Do not open the oven door in the first 15 minutes if possible, so the sponge does not collapse.

For a roulade, spread the same amount of batter on a baking sheet and bake for only about 10 minutes.