Bring the eggs and butter to room temperature.

Preheat the oven to 180–190°C

Sift the cake flour and baking powder together.

Place the room-temperature butter in a bowl and whisk until light and fluffy. Add the salt and sugar, then cream together until pale in color.

Separate the egg into yolk and white. Add the egg yolk to the mixture from step 4 and mix until fully combined.

Add the yogurt and mix until smooth and evenly combined.

Add the mashed banana to the batter.

Place the egg whites in a bowl and whisk until pale and frothy.

Add the dry ingredients to the batter.

Add the meringue from step 8 and gently fold until evenly combined.

Pour the batter into the prepared pan, then gently smooth the surface with a rubber spatula.

Bake in a preheated oven at 180–190°C (350–375°F) for about 10 minutes first.