Preheat the oven to 180degrees and Grease a pan.

Combine the melted butter,melted chocolate,yogurt sugar, vanilla essence,,all purpose flour,coco powder, baking powder, and salt. And mix.

Spread the batter into the prepared greased pan.

Decorate with chopped walnut if desired.

Bake in preheated oven for 25 to 30 minutes or until a toothpick inserted in the center comes out with crumbs, not wet.

Cool on wire rack