In a small saucepan, melt the butter on low flame and let it cool down.

In a bowl, mash the bananas with a fork. If they are ripe it should be quite easy, otherwise use a blender and blend the bananas until soft and creamy.

Whisk into the batter, in this order, yoghurt, eggs, sugar, vanilla extract, cinnamon and salt.

Sift the flour with the baking powder and add it little by little, to avoid lumps. Whisk well.

Stir in, at last, the melted butter.

Grease or line with parchment paper a 20 cm (8 inch) round mould, then scrape the batter inside.

Bake for 45 to 50 minutes, until golden brown and soft, or until a skewer comes out clean and dry.

Let it cool down completely before dusting with icing sugar.