Chocolate sponge cake

Gather and measure your ingredients before starting.
Sift the flour, the cocoa powder, and the baking powder together.
Melt the butter.
For easy cleanup and removal of the cake, line the baking pan with parchment paper and spray with non-stick baking spray.
Preheat oven to 175C (350°F) with the rack in the center of the oven.
Whip the eggs: Add 4 eggs and a pinch of salt to a mixer bowl fitted with a whisk attachment and whip the eggs until slightly foamy.
Slowly pour the sugar into the eggs and continue whipping for about 15 minutes or until the mixture forms a ribbon that doesn't disappear for about 3 seconds when you lift off the whisk.
Fold in the flour: Add the flour mixture into the whipped eggs in halves and carefully fold until almost no streaks of flour are seen.
Add the melted butter and carefully fold until all butter is incorporated. Do not overmix.
Pour the batter into the lined and greased baking pan and quickly swirl the pan back and forth couple of times to even out the batter.
Bake on the middle rack for about 25 minutes or until a toothpick inserted in the middle comes out clean.
Once the cake is baked, remove it from the oven and allow to sit inside the pan for 5 minutes before removing it.
Remove it from the pan and invert it straight onto the cooling rack, then peel off the parchment paper and allow to cool completely.

To fold in the flour, use a large spoon or spatula and work from under the batter and bring it over as you invert the spoon to pour the batter on top.
Do not over-mix to prevent the cake from becoming dense.
Do not open the oven door sooner than 15 minutes into the baking process to prevent deflating and shut the oven door slowly, in order not to disturb the rise of the cake.
For even layers, use a cake ring to cut the cake