Preheat oven to 180 degrees. Grease an 8 inch pan well, sprinkle with cocoa powder.

Cut the orange into half. Squeeze out all the juice that you can. Grate the orange zest till you get one tbsp zest. Keep aside.

In a bowl, whisk together the flours, baking powder, baking soda and salt. Set aside.

Melt the butter and chocolate on low flame. Allow to cool slightly.

Break in one egg at a time and whisk well after each addition.

Add in the sugar and whisk till dissolved. Add in the orange juice and zest and mix well. Whisk in the yogurt.

Add the wet ingredients into the dry ingredients and fold well till combined. The batter will be thick. Pour into the pan and flatten the top.

Bake for 40 minutes or till skewer comes out clean when tested in the center.

Allow to cool in the pan for 15 minutes. You will see the sides closing in. Slowly, tip onto a cooling rack and allow to cool completely.

For the glace, mix all the ingredients together into a thick liquid. Pour into the center of the cake, allowing it to fall to all sides. Allow to cool and set.

Slice and serve!