Sponge Cake

Preheat the oven to 150°C (fan). Prepare a springform pan (line the base with baking paper or grease it).

Separate the eggs and place the egg whites in a clean, fat-free mixing bowl.

Whisk the egg whites with 5 tbsp hot water until stiff, gradually letting the sugar fall in and continue whisking until it has dissolved.

Gently fold in the egg yolks briefly, only until just combined.

Mix the flour with the baking powder, sift it over the mixture and gently fold in to retain as much air as possible.

Pour the batter into the springform and smooth the surface.

Bake for about 20–25 minutes, until a skewer comes out clean; then remove from the oven and let cool.